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.
03 - Beat in eggs one at a time, then mix in vanilla extract until fully incorporated.
04 - In a separate bowl, whisk together all-purpose flour, baking powder, and salt.
05 - Gradually add dry ingredients to wet ingredients, mixing until just combined. Do not overmix.
06 - Press two-thirds of the dough evenly into the bottom of the prepared pan, creating a smooth layer.
07 - Spread strawberry jam evenly over the dough layer, leaving a small border around edges.
08 - Crumble remaining dough over jam layer and press gently to adhere.
09 - Bake for 23–27 minutes until edges are golden brown and center is set.
10 - Let cool completely in pan on wire rack before glazing.
11 - Whisk together powdered sugar, milk, and vanilla extract until smooth and pourable.
12 - Drizzle glaze evenly over cooled bars and immediately sprinkle with colorful sprinkles.
13 - Allow glaze to set for 15 minutes, then cut into 16 bars and serve.