Peanut Butter Cupcakes with Strawberry Filling

Steps

1. Make the filling first: in a small saucepan, stir the strawberries, 40 g of the granulated sugar (a little under half), the cornstarch and the lemon juice. Cook over medium heat, stirring, until bubbling and thick, about 6 minutes. Mash lightly, spread on a plate and chill at least 30 minutes.
2. While the filling cools, heat the oven to 350°F (175°C) and line a 12-cup muffin pan with paper liners.
3. In a bowl, whisk the flour, baking powder, baking soda and 3 g of the salt (three quarters of it).
4. In a large bowl, beat 130 g of the peanut butter (a little over half) with 57 g of the butter (half), the brown sugar and the remaining 50 g of granulated sugar until fluffy, about 3 minutes.
5. Beat in the eggs one at a time, then 8 g of the vanilla (two thirds).
6. Add the flour mixture in three parts, alternating with 180 g of the milk (all but a splash) in two parts, mixing on low just until no dry flour remains.
7. Divide the batter among the liners, filling each about two thirds full. Bake 18 to 21 minutes, until a toothpick in the center comes out clean.
8. Cool the cupcakes in the pan 5 minutes, then on a rack until completely cool, about 1 hour.
9. Make the frosting: beat the remaining 100 g of peanut butter with the remaining 57 g of butter until smooth. Beat in the powdered sugar, the remaining 4 g of vanilla, the remaining 1 g of salt and the remaining 20 g of milk until fluffy.
10. Use a small knife or apple corer to cut a cone about 1 inch deep from the top of each cupcake. Spoon the chilled strawberry filling into the holes, dividing it evenly.
11. Pipe or spread the frosting over each cupcake to cover the filling, then sprinkle with the chopped dry-roasted peanuts.