Preheat oven to 350°F and grease or line your baking sheet.
In a bowl, cream together the softened butter and sugar until fluffy. Beat in the eggs one at a time.
In a separate bowl, whisk together the flour, baking powder, salt, and lemon zest.
Add the dry ingredients and lemon juice to the butter-egg mixture in alternating additions, beginning and ending with the dry ingredients.
Gently fold in the washed blueberries and spread the batter evenly on the sheet.
Bake for about 30–35 minutes, or until golden brown and a toothpick inserted into the center comes out clean.
Let the cake cool. Whisk together the powdered sugar and lemon juice until smooth to make a glaze. Spread it over the cooled cake.
Garnish the blueberry lemon cake with fresh blueberries and lemon zest, as desired.
