1
Position a rack in the center of the oven and heat the oven to 350°F. Coat the cups of a muffin tin with nonstick baking spray or brush generously with melted butter.

2
Sift together the flour, baking powder, and salt into a medium bowl.

3
In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl, using a handheld mixer), cream the butter and sugar on medium speed until light and fluffy, about 3 minutes.

4
Mix the egg, crème fraîche, lemon zest, and juice together in a small bowl with a fork or small whisk. Add to the creamed butter and mix until fully combined, about 2 minutes; the batter will appear a little lumpy. Add the dry ingredients in two batches, mixing well after each addition. Scrape down the sides and bottom of the bowl and the paddle attachment. Use a rubber spatula to fold in the blueberries to avoid crushing them.

5
Using an ice cream scoop or a large spoon, scoop about 1/3 cup batter into each muffin cup. Pick up the muffin tin and knock it firmly against the work surface a couple of times to level the batter and release any air pockets. Sprinkle the top of each muffin with 1/4 teaspoon sugar.

6
Bake for 13 minutes, then rotate the muffin tin and bake for an additional 13 minutes, or until a toothpick inserted in the center of a muffin comes out clean. Cool the muffins in the pan on a cooling rack for 15 to 20 minutes before removing them

See more at http://www.seriouseats.com/recipes/2013/09/blueberry-meyer-lemon-muffins.html