01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
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 - Beat in the egg and vanilla extract until fully incorporated and the mixture is 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 ½ teaspoon of strawberry jam in the center of half the dough rounds, then top each with a second flattened dough round. Pinch the edges firmly to seal and gently press to enclose the jam inside.
07 - Place the filled cookie shells on the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
08 - Bake for 12 to 13 minutes, or until the edges are just turning golden. 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, and vanilla extract until smooth and thick but still pourable. Adjust milk quantity 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. Allow glaze to firm up before serving.