In food processor, cream softened butter, 1/2 cup granulated sugar and 1/8 teaspoon salt. Add 2 cups flour and pulse until it forms a loose ball. Press into bottom of 9 X 13 pan, going about 1/3" up the sides.
Bake crust for 15-20 minutes, until very lightly browned.
While crust is baking, beat eggs. Mix in 2 1/2 cups granulated sugar, lemon juice, lemon zest, 3 Tablespoons flour, corn meal, 1/8 teaspoon salt, vanilla extract, and Cointreau (if using). Whisk well, making sure there are no lumps. Pour over crust. Return to oven and bake 30-35 minutes, until lightly set and lightly browned around the edges.
Let cool completely on wire rack. Cut into squares, dust with powdered sugar and top with fresh raspberries.