1 clam shell of raspberries, washed, dried, and sliced
Preheat the oven to 350 F. Line two baking sheets with parchment paper. Have a pastry bag with a plain tip (about 1/2 inch) ready. In a blender or food processor, grind together the powdered sugar and almond powder/ meal to make sure there are no lumps. Add the red food coloring into the granulated sugar and mix until combined. In the bowl of a standing electric mixer, beat the egg whites until they begin to rise and hold their shape. While whipping, beat in the dyed sugar until very stiff and firm, about 2 minutes. Carefully fold in the dry ingredients, in two batches, into the beaten egg whites with a flexible rubber spatula. When the mixture is smooth and there are no streaks of egg whites, stop folding and scrape the batter into the pastry bag (the batter should resemble thick magma/ lava). Pipe the batter on the prepared baking sheet in 1 inch circles (about 1 tbsp. each), evenly spaced 1 inch apart. Tap the baking sheet a few times on the counter to flatten the macarons. Let them sit in the open air for about 30 minutes then bake for 10 - 12 minutes. Let cool completely before removing them.
To make the custard, whip everything together until it is well combined and begins to thicken, about 3 - 5 minutes. Place in the refrigerator to cool and thicken some more until ready for use. To assemble, organize the macarons into similar sized pairs. Use a piping bag or a spoon to put some custard on one side of the macaron pair. Top it with some halved raspberries and smoosh (if that's a technical term) lightly with the other pair.