1. Preheat oven to 425 degrees. 2. Line a muffin tin with paper cups, or spray well with cooking spray. 3. Whisk together flour, sugar, baking powder, baking soda, salt, and lemon zest until well combined. 4. Add vegetable oil, egg, milk, sour cream, vanilla, and lemon juice. Stir until just combined. 5. Fold in blueberries. 6. Divide among evenly into 10 prepared muffin cups of your muffin tin. 7. Gently add ½ teaspoon of prepared lemon curd to the center of each muffin. 8. Bake at 425 for 5 minutes, then reduce heat to 350 for 18-20 minutes, until a toothpick inserted in the center (juts off from lemon curd) comes out clean. 9. Cool in pan for 5-10 minutes, then gently move to a wire rack to cool completely.