Preparation

• Preheat the oven to 400°F (204°C). Line muffin cups with paper liners for 8 big muffins, 10 standard, or 22 mini. Lightly grease the tops of the muffin tin.
• Use a microplane or citrus zester to remove the zest from the lemon. Add the zest to a small bowl with the sugar and rub it in.
• Whisk the flour, lemon sugar, baking powder, and salt in a large bowl.
• Add the oil to a measuring jug, crack in the egg, and pour in enough milk to reach the 1-cup line. Add the vanilla extract and whisk until combined.
• Add the wet ingredients to the dry ingredients and stir gently until just combined.
• Gently fold in the blueberries and about 2 tablespoons of fresh lemon juice.
• Divide the batter between the muffin cups and sprinkle a little sugar on top. Optionally add a thin lemon slice and more sugar on top.
• Bake muffins for 15 to 20 minutes or until a toothpick inserted comes out clean. Transfer to a cooling rack.