Blueberry, White Chocolate and Lemon TART-CAKENs

I had some extra lemon buttercream icing on hand recently and to use it up, I decided to design a piecaken that included lemon buttercream. So I pulled out The Flavour Thesaurus (written by Niki Segnit) and looked for lemon pairings.  I looked no further when I saw lemon & blueberry because I make a mean white chocolate and blueberry tart, and I knew that altogether, it would be a great pairing.

So I made mini versions of the blueberry-white chocolate tarts and popped them into vanilla cupcakes, and topped the whole thing with the lemon buttercream.  The end result was delicious! 

Here is the how-to:
Before you start: Start one day in advance to make your lemon buttercream!


Recipe for Blueberry-White Chocolate & Lemon Cupcakes

What you need:

For the lemon icing:

• 1/2 lb of unsalted butter, at room temperature & softened.
• 1/4 cup of canola oil
• 2 cups of sifted icing sugar
• 2 whole lemons with peel on, washed.

For the tart filling:

• 2 cups blueberries
• 1 tbsp. lemon juice
• 1/3 cup of granulated sugar

For the tart dough, see the tart recipe in this Chatelaine recipe, and have these ingredients on hand:

• 1 and 1/4 cup of unbleached all-purpose flour
• 2 tbsp. granulated sugar
• 1/2 cup cold, unsalted butter
• 1 egg yolk

For the cupcake recipe, use a cake package mix or check the ingredients on this recipe.

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Instructions:

1. Make the lemon buttercream icing. Start by taking two washed lemons and peeling off large pieces of the skin with a vegetable peeler. Place 2 cups of icing sugar into a bowl and add the lemon rinds to the icing sugar.  Squeeze the juice out of both lemons and add to your icing sugar (through a sifter to get the seeds and pulp out).  Stir until well mixed and the icing sugar is wet.  Let soak overnight. The next day, use a fork to remove the pieces of rind from the icing sugar.  In a separate bowl, beat 1/2 1b of unsalted softened butter until fluffy.  Add 1/4 cup of canola oil and beat again until fluffy, using a spatula to work in the butter. Slowly add the lemon icing sugar and beat until fluffy, being sure to incorporate the butter from the bottom of the bowl with a spatula, so no lumps form. Cover with plastic wrap and set aside until ready to use.

2. Make the crust. Make the crust recipe in this Chatelaine tart recipe for a shortbread tart (I can't give mine away since it is a business secret, but this is close and will work just as well). Then, cut small circles with a round drinking glass and place them into a greased mini cupcake pan, ensuring the tart dough comes up over the sides (the dough can shrink while cooking in the oven, so you want to be sure to have a good ridge for your tart). Bake for 12 to 15 minutes at 350 degrees F or just before they start to brown. Let cool on a cooling wrack for 10 minutes then pop out onto the counter.  If you let these cool completely in the pan, you may have a harder time getting them out.  It is best to take them out while still warm.

3. Cook the blueberry filling. Place 2 cups of frozen blueberries in a small saucepan on the stove. Add 1/3 cup of granulated sugar and 1 tbsp. of lemon juice.  Simmer on the stovetop for 15 minutes, stirring occasionally. Once done, take off the element and let it cool a bit. Once cooled, scoop small spoonfuls of cooked blueberries into the centre of each tart crust.  Leave a slight ridge (about 1/8" to 1/4") for room for white chocolate. Let cool in the fridge while preparing the white chocolate.

4. Melt the white chocolate. Normally I would use a white chocolate ganache (white chocolate and cream combined) to top this tart, but a ganache would just melt inside the cupcakes, so hardened white chocolate is a better solution. Melt 8 ounces of chopped white chocolate in the microwave for 1 minute and 55 seconds on half power.  Take out and stir until fully melted. Add back into the microwave for only five second intervals if not yet melted and stir until melted. Place in a Ziplock sandwich bag, seal the bag and then cut a small hole in one of the corners.  Through the hole, squeeze white chocolate to fill and seal each blueberry tart. Let cool until the white chocolate hardens (in the fridge if necessary).


5. Make vanilla cupcakes. Use your favourite recipe or a cake mix.  Try this lemon cupcake recipe from the Chatelaine Magazine website, and leave the lemon in or take it out - whatever you like.  Line cupcake pan for medium/large cupcakes with large cupcake papers. Then pour a little batter into the bottom of the cupcake papers, and place a blueberry-white chocolate tart inside and press down.  Scoop more batter on top of the tart to fill in the sides and top.  Bake for 15 minutes in the oven or until the cupcake bounces back when you touch it (a little undercooked may be tastier, as the outside of the cupcake can cook quickly).

6. Ice and serve. Let the cupcakes cool then decorate with icing using a cut piping bag or freezer bag. Top with white chocolate shavings, caramelized lemon zest or fresh blueberries!