Prep. time: 20 minutes
Waiting time: 30 minutes
Cooking time: 12 minutes for macarons

The night before, separate the egg whites from the yolks and keep the whites at room temperature in an airtight container. Although not essential, this step will increase your chance of making successful macarons.

Macarons keep very well in the freezer; remove them 10-15 minutes before serving.

Macaron shells

1. Preheat the oven to150°C / 300°F.
2. Blend the powdered almonds and icing sugar in a blender for one minute and pass through a sieve. 
3. Place the egg whites into a mixer bowl with a pinch of salt and beat slowly until foamy. Increase the speed and continue beating until the whites form stiff peaks and come away from the side of the bowl.
4. Add the sugar and food coloring and beat for a few moments more to reform the peaks.  
5. Gently fold the almond mixture into the beaten egg whites with a spatula. The mixture should be smooth and thick and should form a ribbon. 
6. Place the mixture into a piping bag and pipe out the macaron shells on a baking sheet lined with parchment paper. Leave space between them since they will expand when baked. 
7. Let cool on the counter for about 30 minutes so that they form a crust. The shells should no longer stick to your fingers when you touch them.
8. Bake in a preheated oven at 150°C / 300°F for 7 minutes; rotate the tray and bake another 5 minutes.
9. Remove from the oven and gently lift the parchment paper from the pan and place on a damp surface.
10. Let cool before removing the shells.

Preparing the filling

1. Soak the gelatin sheet in cold water.
2. Combine 350 g blueberries with half the sugar in a saucepan and bring to a boil for 3 minutes. Off the heat, briskly stir in the lemon juice and remaining sugar. Return to the heat and boil another 10-12 minutes, then remove from the heat. Check whether the jam is sufficiently cooked by placing a drop on a cold plate: it should set quickly.
3. Stir in the drained gelatin sheet, mix well, and cool completely. 

Assembling the macarons

1. Put the jam into a piping bag and pipe a layer on one shell.
2. Place a blueberry in the middle of the jam.
3. Cover with a second shell of the same size.

Store the macarons in a cool place. They're even better the next day.