In the bowl of a stand mixer, combine until crumbly:
1-1/4 cups flour
1/2 cup sugar
1/2 tsp. baking soda
1/2 tsp. salt
6 Tbl. real butter (cold), cut into pieces
In a separate bowl, whisk together:
1 whole egg
1 egg yolk
1 tsp vanilla
2 Tbl. milk
1/4 cup sour cream
1/4 cup vegetable oil
Add wet mixture to crumbly mixture and mix on low just until combined. Don't overmix. Using small scoop (about 1-1/2 Tbl.), spoon batter into prepared pans...don't fill them more than half-way...the streusel will fill the rest. Sprinkle each muffin with plenty of streusel topping before baking. There will be a lot of streusel topping...use all of it!
For streusel topping, combine:
1-1/4 cups flour
2/3 cup sugar
1 Tbl. cinnamon
2 Tbl. milk
1/4 cup sour cream
1/4 cup vegetable oil
Add wet mixture to crumbly mixture and mix on low just until combined. Don't overmix. Using small scoop (about 1-1/2 Tbl.), spoon batter into prepared pans...don't fill them more than half-way...the streusel will fill the rest. Sprinkle each muffin with plenty of streusel topping before baking. There will be a lot of streusel topping...use all of it!
For streusel topping, combine:
1-1/4 cups flour
2/3 cup sugar
1 Tbl. cinnamon
1/4 tsp salt
1/2 cup butter, MELTED
1/2 cup butter, MELTED
