1. Preheat the oven to 350°F and line an 8-inch square baking pan with parchment paper. Lightly grease the parchment.

2. Whisk the flour, baking powder, and salt in a medium bowl.

3. In a separate bowl, beat the softened butter and granulated sugar until creamy and light.

4. Add the eggs one at a time, mixing well after each addition.

5. Mix in the lemon juice and lemon zest until combined.

6. Fold the dry ingredients into the wet mixture just until a soft batter forms.

7. Spread the lemon batter evenly into the prepared baking pan.

8. In a small saucepan, combine raspberries, raspberry preserves, sugar, lemon juice, and cornstarch.

9. Cook over medium heat, stirring often, until the raspberries break down and the mixture thickens slightly.

10. Let the raspberry topping cool for a few minutes, then gently spread it over the lemon batter.

11. Bake for 28 to 34 minutes, or until the edges are lightly golden and the center is set.

12. Cool completely, then chill for at least 1 hour for cleaner slices.

13. Whisk powdered sugar with lemon juice or milk until smooth.

14. Drizzle the glaze over the chilled bars, let it set, then slice and serve.