4Tablespoonsunsalted butterroom temperature, cut into small pieces
For the muffins:
8.5ouncesall-purpose flour241g, about 2 cups
2teaspoonsbaking powder10g
½teaspoonsalt4g
4Tablespoonsmelted, cooled unsalted butter114g, 1/4 cup
2ouncesvegetable oil1/4 cup
8ouncesgranulated sugar230g, 1 cup
2largeeggs
4ounceswhole milk120ml, 1/2 cup
2teaspoonsvanilla extract
Instructions
Preheat oven to 425°F. Lightly spray 12 muffin cups with non-stick spray, or line cavities with paper liners.
Make the topping
In a medium bowl, use your fingers to combine topping ingredients until completely incorporated. Mixture should be moist but crumbly and hold together when squeezed between your fingers. Keep in refrigerator until ready to use.
Add dry ingredients and using a wooden spoon or rubber spatula, stir just until combined. If you still see small streaks of flour that's okay.
Let batter rest in the bowl for 20 minutes.
Scoop batter into prepared muffin tin. Sprinkle generously with streusel topping, pressing down gently on the tops to ensure that it sticks. Each cup should be full once the streusel is added.
Bake muffins at 425 F for 5 minutes. Then without opening the oven, reduce the temperature to 350 F and bake another for 12-14 minutes, or until a toothpick inserted in the center comes out clean.
Cool for 5 minutes in pan, then remove to wire rack to cool completely.
When making the streusel topping, you can cut the butter in using two butter knives scissor style, or use a pastry cutter. I actually just use my fingers. Once the butter disappears you will be able to pinch the topping and it should hold together.
Use a kitchen scale to measure your ingredients. Excess flour will absorb the surrounding liquids, leaving you with dry, crumbly, and even dense muffins. It's very easy to over measure flour. If you do not own a scale, use the scoop and sweep method. Scoop your flour into the measuring cup with a spoon until it is overflowing. Then, level it off with the flat end of a butter knife. Do not pack down your flour in the cup.
Letting muffin batter rest gives the flour time to fully absorb the liquid, which leads to a smoother batter and a softer, more tender crumb. It also allows the gluten to relax, helping prevent dense or tough muffins, while slightly thickening the batter so it bakes up taller with better domed tops.