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 distributed.
03 - In a large mixing bowl, beat the softened butter and granulated sugar with an electric mixer on medium speed until light and fluffy, approximately 3 minutes.
04 - Add the egg and vanilla extract to the butter mixture. Beat until fully combined and smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until a soft, cohesive dough forms. Do not overmix.
06 - Scoop 2-tablespoon portions of dough and roll into balls. Flatten each ball slightly in your palm. Place 1/2 teaspoon of strawberry jam in the center of half the dough rounds. Top each filled round with a second dough disc, pinch the edges firmly to seal, and gently flatten to enclose the jam.
07 - Place the assembled cookies on the prepared baking sheets, spacing them approximately 2 inches apart to allow for spreading.
08 - Bake for 12 to 13 minutes, or until the edges are just turning golden. Allow cookies to rest on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
09 - In a small bowl, whisk together the powdered sugar, milk, and vanilla extract until smooth and thick yet pourable. Adjust milk as needed to reach desired consistency.
10 - Drizzle or spread the glaze over each cooled cookie. Immediately sprinkle with crushed freeze-dried strawberries or colorful sprinkles before the glaze sets.