1. In a small bowl, stir together 1/4 cup of the sugar and the lemon zest. Set aside.
2. Preheat the oven to 425°F with a rack in the middle. Spray a 12-cup muffin pan with cooking spray (or line 12 muffin cups with paper liners).
3. In a small saucepan over medium heat, bring 1 cup of the blueberries and 1 teaspoon of the sugar to a simmer. Cook, mashing occasionally, until thickened, about 5 minutes. Let cool to room temperature, about 10 minutes.
4. In a large bowl, whisk together the flour, baking powder, and salt. In a medium bowl, beat together the remaining 1 cup sugar, eggs, oil, milk and vanilla until smooth. Add to the flour mixture and stir just until combined. Fold in the remaining blueberries. Pour the batter into the muffin cups until two-thirds full. Spoon about 1 teaspoon of the blueberry compote into each muffin batter center and, using a fork, swirl. Sprinkle generously with the lemon sugar. Bake until until a toothpick inserted into the center comes out clean, 16-18 minutes. Let cool on a rack before serving. (The muffins can be frozen in an airtight container for up to a month.)