1 dozen vanilla cupcakes (I always make these white velvet cupcakes, they’re the best I’ve ever had)
1.5 cups chopped fresh strawberries
2 tbsp vanilla sugar
2 tbsp freshly squeezed lemon juice
6 egg yolks
1.5 cups sugar
½ cup water
1.5 cups unsalted butter, diced (3 sticks)
Combine the chopped fresh strawberries with the sugar and lemon juice, and give it a good stir. Let it sit for 15 minutes at room temperature. This is called macerating, and we are softening the strawberries and intensifying their flavor.
Puree the strawberries in a food processor or blender, taking care to leave some small chunks of strawberry. Pour the mixture in a fine mesh strainer set over a bowl, letting some of the excess liquid drain. Set the drained pureed strawberries aside.
In a stand mixer fitted with the whisk attachment, beat the egg yolks on high speed for 8 minutes until they are very pale. In the meantime, combine the sugar and water in a heavy bottomed saucepan over medium heat, and let the sugar syrup simmer toward the soft ball stage, which is 238 degrees on an instant read thermometer. When both the egg yolks and the sugar syrup are ready, pour the sugar syrup into the mixing bowl (the mixer should still be on high speed), aiming as best as you can to pour between the wire whisk and the side of the bowl. Now, touch the bottom of the bowl. It’s pretty hot, right? Beat the egg yolk sugar mixture until the bowl feels neither hot nor cold (about 5 minutes). The egg yolk sugar mixture will be very runny at this point.
Turn the mixer down to medium and add two tbsp of the strawberry puree. Add the butter, a couple cubes at a time to the bowl, over the course of 10 minutes. Wait until each installment of butter is absorbed until you add the next batch. Do a final taste and see if you would like to add any more strawberry puree. Pipe or spread your buttercream on your cupcakes, and enjoy!