Blueberry Muffins

Two Saturdays ago, half of my lab had to go into work for a big radioactivity experiment. I had seen this Blueberry Muffin recipe in Cook's Illustrated and thought this was the perfect opportunity to try it out. Maybe because it was early on a Saturday, but I totally messed up making this recipe. In my defense, I think the directions could have been a tad more clear (I've amended the recipe below). Despite my errors, they turned out delicious! I'm sure they'd be even better made the right way :)

The idea behind this recipe, according to the author, is to have a blueberry muffin recipe that works with any kind of blueberry - even the 'watery supermarket kind.' To do this, she came up with a simple jam that you swirl into the batter before baking. She also provided a few options for topping the muffins. I went with the lemon-sugar as listed in the original recipe, but I'd love to try the streusel topping next!
Best Blueberry Muffins

Makes 12 muffins

Ingredients:
For the Lemon-Sugar Topping:
1/2 cup (2 1/3 ounces) sugar
1 1/2 teaspoons finely grated lemon zest from 1 lemon


For the Muffins:
2 cups (about 10 ounces) fresh blueberries, picked over*
1 1/8 cups (8 ounces) plus 1 teaspoon sugar
2 1/2 cups (12 1/2 ounces) unbleached all-purpose flour
2 1/2 teaspoons baking powder
1 teaspoon table salt
2 large eggs
4 Tablespoons (1/2 stick) unsalted butter, melted and cooled slightly
1/4 cup vegetable oil
1 cup buttermilk**
1 1/2 teaspoons vanilla extract

Notes:
*To use frozen blueberries, substitute 2 cups frozen blueberries for fresh. Cook 1 cup berries as directed in step 3. Rinse remaining cup berries under cold water and dry well. In step 4, toss dried berries in flour mixture before adding egg mixture.

**If buttermilk is unavailable, substitute 3/4 cup plain whole-milk or low-fat yogurt thinned with 1/4 cup milk. I made my own buttermilk by adding 1 Tablespoon white vinegar to 1 cup of skim milk.

Directions:
Make the topping:
1. Stir together sugar and lemon zest in a small bowl until combined; set aside.
Make the muffins:
2. Adjust oven rack to upper-middle position and heat to 425F. Spray standard muffin tin with nonstick cooking spray. I used a silicon muffin pan with muffin liners.

3. Bring 1 cup blueberries and 1 teaspoon sugar to simmer in a small saucepan over medium heat. Cook, mashing berries with spoon several times and stirring frequently, until berries have broken down and mixture is thickened and reduced to 1/4 cup, about 6 minutes. Transfer to small bowl and cool to room temperature, 10 to 15 minutes.

4. Whisk flour, baking powder, and salt together in a large bowl.

5. In a separate, medium-sized bowl, whisk remaining 1 1/8 cups sugar and eggs together until thick and homogenous, about 45 seconds. Slowly whisk in butter and oil until combined. Whisk in buttermilk and vanilla until combined.

6. Using a rubber spatula, fold egg mixture and remaining cup blueberries into flour mixture until just moistened. Batter will be very lumpy with a few spots of dry flour; do not overmix.

7. Use an ice cream scoop or large spoon to divide batter equally among prepared muffin cups. Batter should completely fill cups and mound slightly.

8. Spoon a teaspoon of cooked berry mixture into the center of each mound of batter. Using a chopstick or skewer, gently swirl berry filling into batter using figure-eight motion. Sprinkle lemon-sugar evenly over muffins. Try not to sprinkle evenly over pan like I did - I was in a hurry :)
9. Bake until muffin tops are golden and just firm, 17 to 19 minutes, rotating muffin tin from front to back halfway through baking time. Cool muffins in muffin tin for 5 minutes, then transfer too wire rack and cool 5 minutes before serving.

Streusel Topping

Follow Best Bleuberry Muffin recipe, omitting Lemon-Sugar Topping. Prepare streusel by combining 3 Tablespoons granulated sugar, 3 Tablespoons dark brown sugar, a pinch of table salt, and 1/2 cup plus 3 Tablespoons (3 1/2 ounces) unbleached all-purpose flour in a small bowl. Drizzle with 5 Tablespoons warm, melted unsalted butter and toss with a fork until evenly moistened and misture forms large chunks and some pea-sized pieces throughout. Proceed with recipe as directed, sprinkle streusel topping over muffins before baking.

Source: Adapted from Cook's Illustrated