Small-Batch Blueberry Muffins

Name: Small-Batch Blueberry Muffins
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Cuisine: American
Ingredients: ¾ cup blueberries (frozen or fresh); 1 cup all-purpose flour; 1 teaspoon baking powder; ¼ teaspoon salt; 1/4 cup sugar; 2 tablespoons brown sugar; 4 tablespoons unsalted butter (softened); 1 large egg; ¼ cup milk; ½ teaspoon vanilla extract; ¼ teaspoon lemon zest; 2 tablespoons sugar; 1 tablespoon all-purpose flour; ¼ teaspoon ground cinnamon; 1 tablespoon unsalted butter (diced)