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, incorporating fully 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 wet 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 pan using lightly floured hands or the back of a spoon.
07 - Spread strawberry jam evenly over the dough layer, leaving a small border around the edges to prevent overflow during baking.
08 - Crumble remaining dough between fingers and sprinkle evenly over jam layer. Press gently to adhere.
09 - Bake for 23-27 minutes until edges are golden brown and center appears set. A toothpick inserted should come out clean.
10 - Let bars cool completely in pan on a wire rack, approximately 1 hour, before adding glaze.
11 - Whisk powdered sugar, milk, and vanilla extract in a small bowl until smooth and pourable. Add additional milk 1 teaspoon at a time if too thick.
12 - Drizzle glaze evenly over cooled bars. Immediately sprinkle with colorful sprinkles before glaze sets.
13 - Let glaze set for 15 minutes at room temperature. Cut into 16 bars and serve.