Vernal Equinox Celebration - Blueberry Cupcakes

I'm not a big fan of Easter. Not only because I consider myself an atheist, but also because I resent the Czech traditions related to this holiday... The custom of often drunk men spanking women with willow rods and throwing cold water on them, and women rewarding them with decorated eggs doesn't really appeal to me... On the other hand, who wouldn't like a day off from work? So I decided to celebrate the end of winter, vernal equinox.

...and, about a week ago, I made these blueberry cupcakes with lemon mascarpone frosting, decorated them with chocolate candy eggs... and enjoyed a free Friday and Monday in Prague with Honza, visiting our grandmas and aunties.

By the way, blueberries are good for you. Apart from a lot of other phenols, they contain a chemical called chlorogenic acid, an esther of caffeic acid and L-quinic acid. It is a powerful antioxidant and, in spite of its name, it doesn't contain any chlorine. Its name comes from the Greek xλωρός (light green) and -ϒένος (a suffix which means "giving rise to") - when the chloronergic acid oxidizes, a green colour is produced. 

Blueberry-enriched diet was shown to provide cellular protection against oxidative stress and reduce a kainate-induced learning impairment in rats (Duffy et al., 2008). Antioxidant properties of natural polyphenols are also investigated for their therapeutic potential for Alzheimer's disease (Choi et al. 2012), as the fruit polyphenols have been shown to have beneficial effects on brain aging (Lau et al., 2005).

Vernal Equinox Blueberry Cupcakes with Lemon Mascarpone Frosting

Ingredients (makes for about 12 cupcakes)

     Cupcakes
45 g butter
1&1/2 cup plain flour
3/4 cup frozen blueberries
1/2 cup sugar
1/2 cup plain white yogurt
1/2 cup whole milk
1/8 cup vegetable oil
0.5 tbsp. baking powder
0.5 tsp. vanilla extract* (not the Dr.Oetker clear essence!)
0.5 tsp lemon zest
0.25 tsp. salt
0.25 tsp. baking soda
1 large egg
*the only good vanilla extract I discovered in CZ/SK so far is the one from Marks and Spencers, in the UK I like the one from Dr.Oetker (brownish and thick, available with, or without the vanilla seeds)

     Lemon Mascarpone Frosting
200 g mascarpone cheese
40 g unsalted butter (softened)
6-8 tbsp. powdered sugar
juice from 1/2 lemon
(10 g whipping cream stabilizer (CZ/SK smeta-fix Dr.Oetker) - only if the frosting turns out too runny)

Directions
      Cupcakes
1. Preheat oven to 180°C
2. Whisk together the melted butter and oil
3. Add the egg and whisk to blend
4. Add yogurt, milk, vanilla extract and lemon zest and mix thoroughly
5. Mix the dry ingredients and slowly add the dry mixture to the wet one and whisk thoroughly until smooth
6. Stir in the blueberries
7. Line a cupcake/muffin pan with cupcake cases and fill each one a about 3/4 full
8. Bake for about 20 minutes (toothpick inserted in the centre should come out mostly clean)

     Lemon Mascarpone Frosting
1. Beat butter with a mixer until pale and fluffy (about 3 min)
2. Combine the powdered sugar and lemon juice, if too runny, add some more sugar
3. Add the sugar-lemon mixture to the mascarpone, add butter and whisk until smooth and creamy
4. If too runny, add the whipping cream stabilizer

Apple Cupcakes with Caramel(an, en and in) Buttercream

From the "chemistry-science" perspective, caramel, or, to be more precise, the process of caramelization, seems pretty complicated... Although it is really cool to understand the chemistry behind this golden delight, it might scare you off from trying to cook it on your own. Nevertheless, after my first successful attempt, I can assure you it is actually easier than it looks. Although one must really pay attention to the tiniest details, it is a surprisingly quick process and the end product is definitely worth it.

It all starts with sugar dissolving in water (for the so called "wet caramelization"), and sucrose breaking down into fructose and glucose by hydrolysis. The second step, condensation, is very easy to detect, because you start noticing the aromas coming out of the pot. This signals that glucose and fructose started to break down into smaller, more volatile compounds. You might be able to smell the nutty aroma of furans, buttery smell of diacetyl, toasty fragrance of maltol, and fruity scent of ethyl acetate...  

This second step can be, in theory, accelerated, if you add a little lemon juice to the sugar mixture...the breakdown of fructose and glucose is acid catalyzed, thus adding an acid, such as the citric one, should enable the reaction to occur faster and at lower temperature. I have not tried that, so my recipe below does not include lemon juice... it could, however, be a nice experiment...

Oligomerization is the next step in caramelization process. These reactions further contribute to the development of brown colour and portions of the texture. First, dimerization occurs. In the case of fructose, the dimer is called di-D-fructose dianhydride. There are three different pathways on which these dimers can react further. These differ in the number of water molecules that are lost in the reaction. One of them results in the formation of caramelan (C12H12O9) aggregates of which form small, brown particles about 460 nm in size , another one can form caramelen (C36H18O24), a polymer that has aggregates of 950 nm in size, and the third one produces another polymer called caramelin (C24H26O13) which aggregates in particles that are darker in colour and are about 4333 nm in size. These oligomers assemble into particles and networks and create the unique texture of caramel. The presence of free radicals is believed to be partially responsible for the typical caramel stickiness.

Apple Cupcakes with Caramel Buttercream Frosting

Ingredients (makes for about 12 medium cupcakes)

     Cupcakes
1&1/2 cup plain flour
1 cup grated apples
1 cup brown sugar
1/2 cup vegetable oil
1/8 cup lemon juice
2 tsp. baking powder
1 tsp. vanilla extract* (not the Dr.Oetker clear essence!)
0.5 tsp. salt
0.5 tsp. cinnamon
2 large eggs
*the only good vanilla extract I discovered in CZ/SK so far is the one from Marks and Spencers, in the UK I like the one from Dr.Oetker (brownish and thick, available with, or without the vanilla seeds)

     Caramel Buttercream Frosting & Caramel Topping
170 g unsalted butter (softened)
1/2 cup brown sugar
1/8 cup water
1/8 cup heavy cream
1 tsp. vanilla extract
0.25 tsp. salt
2 large egg whites

Directions
      Cupcakes
1. Preheat oven to 180°C
2. Beat together the eggs and sugar until creamy
3. Beat in the lemon juice, vanilla extract, and oil
4. Mix the remaining dry ingredients and slowly add the dry mixture to the wet one and beat thoroughly until smooth
5. Stir in the grated apples
6. Line a cupcake/muffin pan with cupcake cases and fill each one a about 3/4 full
7. Bake for about 20 minutes (toothpick inserted in the centre should come out mostly clean)

     Caramel/Caramel Topping
1. Bring 1/4 cup sugar and the water to boil, cook and stir with a wooden spoon occasionally until the caramel is dark amber
2. Remove from heat and add cream, salt and 0.5 tsp. vanilla extract, stir with a wooden spoon until smooth
3. Let cool
     Caramel Buttercream
1. Beat butter with a mixer until pale and fluffy (about 3 min)
2. Put the egg whites and 1/4 cup sugar in a heatproof  bowl and set it over a pot of simmering water
3. Whisk until sugar dissolves and remove from heat
4. Whisk the sugar-egg mixture on medium speed for about 5 min
5. Increase the speed to medium-high and whisk until stiff and glossy (about 6 min)
6. Reduce speed to minimum, slowly add beaten butter, whisking well after each addition
7. Whisk in vanilla extract and add about 1/3 (or more) of the caramel and beat until smooth (3-5 min)

Lemon-Lime Essential "Exam" Cupcakes

The genus Citrus (family Rutaceae) comprises of about 140 genera and 1300 species (wow!). The characteristic citrus fruit fragnance is due to flavonoids and limonoids (terpenes) contained in the rind, and the juice which is rich in citric acid that is also responsible for the sharp flavour.  Citrus peel essential oils are a source of bioactive compounds, such as the aforementioned flavonoids or carotenes, coumarins and linalool. These oils are also known for their antioxidant and antimicrobial properties.

For this recipe I chose Citrus limon (lemon) and Citrus aurantifolia (lime)... and I made use not only of their juice, but also of their zest.

My friends from the lab, Veronika and Iva, had a big day on Friday - they have been defending their PhD research projects. Apparently, it is a tradition here in Slovakia that students taking an important exam prepare refreshements for the exam committee... so they are stressed, nevous, spend all their time revising and preparing their presentation and above that, they are supposed to take care of food for their examiners. I would not have problem with that, as cooking and baking relaxes me, brings me joy, and would probably calm me down and help me focus, but I can imagine it is not how the majority of students like to spend their time before an exam... So I offered my services... 
...and voilà - lemon-lime cupcakes!

(I also made some mocha cupcakes with espresso-mascarpone frosting (probably my next post).)

Lemon-Lime Cupcakes with Creamy Lemon Frosting

Ingredients (makes for about 18 medium cupcakes)
     Cupcakes
100g white sugar
1&1/2 cup plain flour
1/2 cup milk
6 tbsp. vegetable oil
2 tbsp. lemon zest
1 tbsp. lime zest
2 tbsp. lemon juice
1 tbsp. lime juice
1.5 tsp. baking powder
0.5 tsp. salt
2 large eggs

     Creamy Lemon Frosting
200 g mascarpone
2-4 tbsp. powdered sugar
lemon juice

Directions
      Cupcakes
1. Preheat oven to 180°C
2. Mix oil, sugar, lemon and lime zest and salt (medium speed, app. 2 min)
3. Mix in the lime and lemon juice and eggs (medium speed, app. 2 min)
4. Add flour and baking powder to the mixture, keep beating while adding the milk until the dough is smooth
5. Line a cupcake/muffin pan with cupcake cases and fill each one a bit over 3/4 full
6. Bake for about 20 minutes (toothpick inserted in the centre should come out clean)
     
      Frosting
1. Mix mascarpone with sugar
2. Add lemon juice and mix thoroughly (how much you add depends on how sharp you want the frosting to be, but be careful not to overdo it, as the frosting might become too runny - if this happens, either add more sugar, mascarpone, or both)