Preheat oven to 325°F (165°C).
Grease and flour a 10-inch tube pan.
In a medium bowl, whisk together flour, baking powder, and salt.
Toss blueberries with ¼ cup flour to prevent sinking.
Cream butter and sugar until light and fluffy (5 minutes).
Add eggs one at a time, beating after each.
Mix in vanilla and lemon zest. Flavoring
Alternate adding dry ingredients and milk, starting and ending with flour.
Gently fold in blueberries.
Pour batter into prepared pan and smooth the top.
Bake for 75-85 minutes or until a toothpick comes out clean.
Cool in the pan for 20 minutes before removing.