In a medium bowl, mix the flour, baking powder, salt, and sugar. Set aside.
2 cup All-purpose flour, 1 TBSP Baking powder, 1/2 tsp Salt, 1 cup White granulated sugar
In a large bowl, whisk together the melted butter, oil, vanilla, eggs, sour cream, and buttermilk. Add in the dry ingredients and mix with a baking rubber spatula and mix until almost combined.
1/4 cup Unsalted butter, 1/4 cup Oil, 1 tsp Pure vanilla extract, 2 Large eggs, 1/3 cup Sour cream, 1 cup Buttermilk
In a separate small bowl, mix the frozen wild blueberries and flour together. Pour into the batter and gently mix it in.
1 1/2 cup Wild frozen blueberries, 1 TBSP All-purpose flour
Let the batter rest for 15 minutes to help with rising. Preheat the oven to 425℉. Line two 12 cup muffin pans (or one at a time) with 6 muffin liners. You want them evenly spaced to get a higher rise.
Use a large cookie scoop and use half the batter per 6 muffins and fill the liners all the way to the top. Sprinkle coarse sugar on top.
Coarse sugar
Bake for 5 minutes at 425℉. Then, lower the oven to 350℉ and bake for 10-13 minutes. Bake until a toothpick inserted comes out clean.
Let the muffins sit in the hot pans for 10 minutes before transferring to a cooling rack.