Preheat oven to 350°F (180°C). Grease and line a 9x5-inch loaf pan with parchment paper.
Beat butter, sugar and lemon zest until light and fluffy.
Add eggs one at a time, then mix in vanilla, lemon juice and ricotta until smooth.
Gently fold in flour, baking powder and salt.
Toss blueberries in 1 tbsp flour (so they don’t sink) and gently fold through.
Pour into the pan, smooth the top and bake 50–60 minutes, or until a skewer comes out clean.
Cool for 10 minutes in the pan, then transfer to a wire rack.
Drizzle with icing or dust with powdered sugar.
