Moist Blueberry Muffins

Preheat oven to 350F. Spray a Non-Stick 12-Cup Regular Muffin Pan with floured cooking spray (I prefer the cosmetic look of not using liners so I didn't); set aside. In a large bowl, add flour, baking powder, optional salt, and whisk until combined; set aside. In a separate large bowl, whisk egg until well-combined and light-colored, about 20 seconds. Add 1 cup granulated sugar to the egg and whisk vigorously until thick and homogenous, about 30 seconds; set aside. In a small microwave-safe bowl, melt the butter, about 30 seconds on high power. Allow butter to cool momentarily, about 1 to 2 minutes. Slowly add the butter to the egg-sugar mixture, whisking while adding it; or add it in 2 to 3 additions, whisking after each addition until mixture is combined. Add the vanilla and whisk until combined. Add the sour cream and whisk until smooth and combined, don't overmix; set aside. Add 1 3/4 cup frozen blueberries to the flour mixture, tossing lightly with a spatula to coat them. This helps prevent berries from sinking while baking. Slowly add the egg-sour cream mixture to the flour-blueberries and fold using a spatula until batter comes together, the berries are evenly distributed, and most of the flour bits are folded in (some small spots of flour can remain); don't overmix. Batter will be quite thick. Using a large cookie scoop or cooking-sprayed heaping 1/4-cup measure, equally distribute batter in prepared pan until all batter is gone and has been distributed equally. Top each cup with about 2 blueberries (creates a nice visual appeal). Top each cup with a generous pinch of turbinado or sparkling sugar. This encourages tops to become more golden while baking. Bake for about 30 to 35 minutes (I baked 34 minutes), rotating pan once midway through baking. Bake until muffins are set, cooked through, soft yet springy to the touch, and a toothpick inserted in the center comes out clean, or with a few moist crumbs but no batter. Because the moisture content in the sour cream and the blueberries varies, as do pan sizes, climates, and ovens, bake until done; watch your muffins and not the clock. The frozen berries really cool down this batter, and due to the moisture content and heaviness of the sour cream, these muffins take longer than most to cook. The tops don't get very golden and they stay quite pale so don't judge their doneness by the color of the tops. Allow muffins to cool in pan for about 15 minutes before carefully removing; use a paring knife to help dislodge any stubborn ones. Muffins are best fresh, but will keep airtight at room temp for up to 5 days; or in the freezer for up to 4 months.