Let me tell you, if you want to treat yourself or someone else with something really special you should bake these macarons. Little acidic taste that comes from blueberries combined with white chocolate ganache filling and crunchy texture of macarons will make experience out of this world.
Although this fruit is generally great in baking, have in mind that fresh, frozen, or even dried blueberries won't do the job when making macarons. What I used instead were dehydrated or freeze-dried blueberries and they worked pretty well, both in shells and filling. They produce nice taste and natural purple color. Freeze-dried blueberries are available in Trader's Joe, Whole Foods or Target. I like to make bagels with them too - more about it soon on the blog. Recently I found freeze-dried strawberries in a store and got very excited - still trying to figure it out dessert that I would like to make with them.
140g egg whites, on room temperature for few hours
100g white granulated sugar
160g finely ground almond (almond flour)
240g powdered sugar
10g freeze-dried blueberries powder (pulverized in food processor)
2-3 drops purple food color
200g white chocolate
2 tablespoons butter
1/2 cup heavy cream
10g finely chopped freeze-dried blueberries
Line 3 large baking sheets with parchment paper.
In a bowl combine powdered sugar with ground almond.
In another bowl beat egg whites with electric mixer on medium speed until foamy. Increase the speed and while mixing gradually add granulated sugar in 3 batches, one at a time. Beat on high speed until stiff peaks form.
Stir in nut-sugar mixture and food color using spatula. Do not over mix it. Batter shouldn't be too thick or too lose.
Spoon mixture into pastry bag fitted with a round tip. Pipe rounds, 1-inch apart, on the baking sheets. Let it stand 20-40 minutes, until dry film forms on surface. This is very important stage, if there isn't dry film on surface it will cause macarons to crack while baking.
Preheat the oven. In my oven I bake macarons on 285F. Usually, people do it on 300F. Do not open the oven for first 7 minutes. In my oven, it takes 13 minutes for macarons to be done. You can check if they are done by touching them and moving them, if they break they are not ready to go out. To much of baking is not good either, because they get brown and change their original color.
When shells are done, cool them on wire racks.
Make ganache. Heat heavy cream until it starts to boil. In a bowl, place white chocolate chips and butter cut in small pieces. Pour in hot cream, cover the bowl with lid and wait for few minutes. Then stir ganache until all chocolate is melted. Add chopped freeze-dried blueberries and stir until they start to dissolve. Remove it to fridge for 15 minutes to thicken. Spoon it into pastry bag and fill between two macaron biscuits, making a "sandwich" held together by ganashe.
Store macarons in airtight containers in the fridge.
I took a picture of macaron with a bite just to show you how nice it looks inside. See it bellow.