01 - Preheat your oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving some overhang for easy removal.
02 - In a large bowl, cream together the softened butter and sugar until light and fluffy using an electric mixer or by hand.
03 - Beat in eggs one at a time, then add vanilla extract and mix until fully incorporated.
04 - In a separate bowl, whisk together flour, baking powder, and salt until well blended.
05 - Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
06 - Press two-thirds of the dough evenly into the bottom of the prepared pan using your hands or a spatula.
07 - Spread the jam evenly over the dough layer, leaving a small border around the edges.
08 - Crumble the remaining dough over the jam layer, pressing gently to adhere.
09 - Bake for 23-27 minutes, or until the edges are golden brown and the center is set.
10 - Let cool completely in the pan on a wire rack before glazing.
11 - Whisk together powdered sugar, milk, and vanilla until smooth and pourable. Adjust consistency with more milk if needed.
12 - Drizzle the glaze over the cooled bars and immediately top with sprinkles before the glaze sets.
13 - Let the glaze set for 15 minutes, then cut into 16 bars using a sharp knife.