Preheat the oven to 350 degrees Spray a 9x5 inch loaf pan with nonstick spray. In a bowl, whisk together the flour, baking powder and salt.
In the bowl of an electric mixer, beat the butter and sugar until light and fluffy, about 5 minutes. Beat in the eggs 1 at a time. Beat in the ricotta cheese, lemon juice and vanilla extract until combined.
With the mixer on low speed, beat in the dry ingredients until they are just combined. Do not overmix!
Toss the blueberries with the 1 tablespoon of flour. Add the blueberries to the batter and use a spatula to fold them in.
Spread the batter in the loaf pan. Bake the cake for 55 to 60 minutes, or until a tested inserted in the center comes out clean. Remove the cake from the oven and let it cool for 20 to 30 minutes before inverting it onto a dish, cooling rack or parchment paper. Let it cool completely before glazing.