Very Blueberry Muffins

Thanks to chowhound, I found two recipes that are contenders for my ultimate blueberry muffin recipe. This is the first one. Thanks to the quick blueberry jam, it has a rich blueberry flavour. While I adore the lemon sugar topping, the original also has suggestions for a streusel topping and an orange glaze topping that both sound amazing. Is this the best blueberry muffin recipe? I don't know, I need to try the other one soon! Will I be making it again? Almost certainly!

I cut the recipe in half so I wouldn't be overwhelmed with blueberry muffins (and would have enough blueberries leftover to make the other batch of muffins), but the original is included below. I also cheated with the buttermilk (I haven't seen it in the Metro lately!) and made it by combining 1 cup milk with 1 tbsp lemon juice and letting it sit for 10 minutes or so. The original suggests substituting 3/4 cup plain whole-milk or low-fat yogurt thinned with 1/4 cup milk, which sounds even better, but I went with what I had and have used before.

Very Blueberry Muffins (from the Bitten Word) (from Cook's Illustrated (May/June 2009))

Ingredients
Lemon-Sugar Topping
1/3 cup sugar
1 1/2 tsp finely grated zest from 1 lemon
Muffins
2 cups fresh blueberries, picked over
1 1/8 cups plus 1 teaspoon sugar
2 1/2 cups unbleached all-purpose flour
2 1/2 tsps baking powder
1 tsp table salt
2 large eggs
4 tbsps unsalted butter, melted and cooled slightly
1/4 cup vegetable oil
1 cup buttermilk
1 1/2 tsp vanilla extract

1. FOR THE TOPPING: Stir together sugar and lemon zest in small bowl until combined; set aside.
2. FOR THE MUFFINS: Adjust oven rack to upper-middle position and heat oven to 425 degrees. Spray standard muffin tin with nonstick cooking spray or line with 12 muffin cups.
3. Bring 1 cup blueberries and 1 teaspoon sugar to simmer in 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 large bowl.
5. Whisk remaining 1 1/8 cups sugar and eggs together in medium bowl until thick and homogeneous, about 45 seconds.
6. Slowly whisk in butter and oil with eggs until combined.
7. Whisk in buttermilk and vanilla with eggs until combined.
8. Using rubber spatula, fold egg mixture and remaining cup blueberries into flour mixture until just moistened. (Batter will be very lumpy with few spots of dry flour; do not overmix.)
9. Use ice cream scoop or large spoon to divide batter equally among prepared muffin cups (batter should completely fill cups and mound slightly).
10. Spoon teaspoon of cooked berry mixture into center of each mound of batter.
11. Using chopstick or skewer, gently swirl berry filling into batter using figure-eight motion. Sprinkle lemon sugar evenly over muffins.
12. 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 to wire rack and cool 5 minutes before serving.