Preheat oven to 325 degrees F (165 degrees C). Grease and flour 2 loaf pans.
Combine the flour, baking powder, and salt and set aside.
Beat the butter and 2 1/2 cups sugar with an electric mixer in a large bowl until light and fluffy. The mixture should be noticeably lighter in color.
Add the room-temperature eggs one at a time, allowing each egg to blend into the butter mixture before adding the next. Beat in the almond extract with the last egg.
Pour in the flour mixture alternately with the milk, mixing until just incorporated. Fold in the lemon zest and chopped walnuts, mixing just enough to evenly combine.
Pour the batter into the prepared pans.
Bake in the preheated oven until the loaves are very lightly browned and a toothpick inserted into the middle comes out clean, 60 to 70 minutes.
Mix the lemon juice with the 1/2 cup sugar in a bowl until the sugar has dissolved.
Pour the lemon glaze over the hot cakes; allow to stand for 10 minutes before removing cakes from the pans. Cool before serving.
