01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, allowing overhang for easy removal.
02 - In a large bowl, beat softened butter and granulated sugar together until light and fluffy, approximately 2-3 minutes.
03 - Beat in eggs one at a time, fully incorporating each before adding the next. Stir in vanilla extract.
04 - In a separate bowl, whisk together all-purpose flour, baking powder, and salt until evenly distributed.
05 - Gradually add dry ingredients to the butter mixture, mixing on low speed until just combined. Do not overmix.
06 - Press two-thirds of the dough evenly into the bottom of the prepared baking pan, creating a uniform layer.
07 - Spread strawberry jam evenly over the dough base, leaving a small border around the edges to prevent overflow during baking.
08 - Crumble the remaining dough over the jam layer in small pieces, pressing gently to adhere.
09 - Bake for 23-27 minutes until edges are lightly golden and the center is set. A toothpick inserted should come out clean.
10 - Let the bars cool completely in the pan on a wire rack before adding glaze, approximately 1 hour.
11 - Whisk together powdered sugar, milk, and vanilla extract until smooth and pourable. Adjust milk consistency as needed.
12 - Drizzle the glaze evenly over the cooled bars. Immediately sprinkle with colorful sprinkles before the glaze sets.
13 - Allow glaze to set for 15 minutes, then cut into 16 equal-sized bars. Store in an airtight container.