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, cream softened butter and granulated sugar until light and fluffy using an electric mixer or by hand.
03 - Beat in eggs one at a time, then incorporate vanilla extract until fully combined.
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 just until dough forms and no dry streaks remain.
06 - Press two-thirds of dough evenly into bottom of prepared pan using clean hands or spatula.
07 - Spread strawberry jam evenly over dough base, leaving small border around edges.
08 - Crumble remaining dough over jam layer in small pieces, pressing gently to adhere.
09 - Bake 23-27 minutes until edges are golden brown and center appears set.
10 - Let bars cool completely in pan on wire rack before glazing, about 1 hour.
11 - Whisk powdered sugar, milk, and vanilla until smooth and pourable, adjusting consistency with additional milk if needed.
12 - Drizzle glaze evenly over cooled bars and immediately sprinkle with decorative sprinkles before glaze sets.
13 - Let glaze set for 15 minutes, then lift bars from pan using parchment overhang and cut into 16 equal pieces.