In a medium saucepan over medium heat, add the raspberries, 1/4 cup sugar, and 2 tablespoons lemon juice. Bring the mixture to a gentle boil, stirring often. Once boiling, let it simmer for 8-10 minutes or until it thickens—stir frequently to avoid burning. Once thickened, pour the mixture into a fine-mesh strainer to remove the seeds, and set aside to cool completely.

Preheat your oven to 350°F (175°C) and spray a 9×13 inch baking dish with nonstick cooking spray.

In a medium bowl, combine 1 cup butter, 2 cups flour, and 1/2 cup sugar. Using a pastry cutter, fork, or your hands, blend the mixture until it resembles coarse crumbs. Press the crumb mixture evenly into the bottom of your prepared baking dish. Bake for 15-20 minutes, or until golden and fragrant.

In a large bowl, whisk together 1 1/2 cups sugar, 1/4 cup flour, eggs, 2/3 cup lemon juice, and the cooled raspberry sauce until smooth and well combined.

Once the crust is out of the oven, pour the raspberry filling over it. Return to the oven and bake for an additional 20-25 minutes or until the filling is just set.

Allow the bars to cool completely at room temperature; then chill in the refrigerator for at least 2 hours before cutting them into squares.

When ready to serve, dust lightly with confectioners' sugar.