01 - Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until evenly combined.
03 - In a large bowl, use an electric mixer to beat the softened butter, granulated sugar, and brown sugar on medium speed until pale, light, and fluffy, about 2 to 3 minutes.
04 - Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract until fully incorporated.
05 - Gradually add the dry ingredient mixture to the creamed butter mixture, mixing on low speed just until the dough comes together. Do not overmix.
06 - Scoop 2-tablespoon portions of dough and flatten each into a small disc in the palm of your hand. Place 1 teaspoon of strawberry jam in the center, fold the dough over the filling, pinch the edges to seal completely, and gently roll into a smooth ball.
07 - Place the filled dough balls on the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
08 - Bake for 11 to 13 minutes, until the edges are lightly set but the centers still appear slightly soft. Let the cookies rest on the baking sheets for 5 minutes, then transfer to a wire cooling rack to cool completely.
09 - In a small bowl, whisk together the powdered sugar, milk, vanilla extract, and a drop of food coloring if desired, until a smooth glaze forms. Drizzle generously over the cooled cookies and immediately top with sprinkles before the glaze sets.