Preheat your oven to 350°F (175°C). Grease and flour a standard 9x5 inch loaf pan, or line it with parchment paper.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a large bowl, using an electric mixer, cream together the softened butter and 1 cup of granulated sugar until light and fluffy (about 3 minutes). Beat in the eggs one at a time, scraping down the sides.

Stir in the lemon zest. In a small bowl, whisk together the milk, 1/4 cup lemon juice, and vanilla extract (if using). Alternately add the dry ingredients and the wet mixture to the butter mixture, beginning and ending with the dry ingredients, mixing just until combined.

Gently fold in the raspberries. Pour the batter into the prepared loaf pan. Sprinkle the remaining 2 tablespoons of granulated sugar evenly over the top of the batter.

Bake for 50 to 55 minutes, or until a wooden skewer inserted into the center comes out clean. If the top browns too quickly, loosely tent with foil for the remainder of the baking time.

Let the cake cool in the pan for 15 minutes, then carefully turn it out onto a wire rack to cool completely.

While the cake cools, prepare the glaze: Whisk together the powdered sugar and 3 tablespoons of lemon juice until smooth and pourable. Drizzle generously over the fully cooled loaf cake before slicing and serving.