Preheat oven to 350ºF. Line an 8 ½ x 4 ½ inch loaf pan with parchment, leaving extra paper hanging over side of pan.
In a large mixing bowl or stand mixer, beat together the sugar, butter, eggs, lemon and orange zest, lemon juice, and vanilla extract until well incorporated.
Combine flour, baking powder, and Kosher salt together in a separate bowl. Add blueberries and toss to coat in flour mixture. Stir in the egg mixture and milk until no lumps. Pour into prepared loaf pan.
Bake until a toothpick inserted in the center comes out lean, about 60-70 minutes. Cool bread for 20 minutes.
Meanwhile, make the glaze. Stir together the powdered sugar, lemon juice, and lemon zest until smooth.
Remove the bread from the pan and drizzle with glaze. Slice and enjoy.