Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large bowl, cream the softened butter and granulated sugar with a hand mixer or stand mixer until fluffy and pale, about 2–3 minutes.

Beat in the egg and vanilla until combined and smooth.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry mix to the wet ingredients and stir until just combined; don’t overmix.

Scoop tablespoon-sized portions of dough and roll them into balls. Place them on the prepared sheet about 2 inches apart. Flatten each slightly with your palm.

Press your thumb into the center of each cookie to create a small indentation. Fill each indentation with about 1/2 teaspoon of strawberry jam.

Bake for 10–12 minutes, until the edges are just turning golden but the centers remain soft.

Let the cookies rest on the baking sheet for 3–4 minutes, then transfer to a wire rack to cool completely.

Whisk the powdered sugar and milk together until smooth. If too thick, add a few drops of milk; if too thin, add more powdered sugar.

Drizzle the glaze over cooled cookies and top with sprinkles.

Allow the glaze to set for 10–15 minutes before serving.