Preheat the oven to 350°F (175°C) and grease an 8x8-inch baking dish or pie dish.
Mix wet ingredients: In a bowl, combine cottage cheese, egg, sugar, and lemon zest or vanilla. Stir until well combined.
Add dry ingredients: Gently fold in flour, salt, and baking soda. Mix until just combined—avoid overmixing.
Fold in blueberries carefully to distribute them evenly throughout the batter.
Transfer to the prepared baking dish and spread the batter evenly.
Bake for 30-35 minutes, or until the top is golden and the center is set. Let it cool slightly before serving.