In a large-sized bowl, sift and mix all the dry ingredients, then set aside.
1¾ cup All-purpose flour, ½ cup Quick oats, ½ cup Granulated sugar, ¼ cup Brown sugar, 2 teaspoon Baking powder, ½ teaspoon Baking soda, ½ teaspoon Salt, 1 teaspoon Cinnamon
In a separate bowl, whisk all the wet ingredients, including eggs, oil, melted butter, sour cream, milk and vanilla extract.
2 Eggs, 1 tablespoon Vanilla extract, ½ cup Sour cream, ¼ cup Milk, ⅓ cup Oil, 2 tablespoon Butter
Add the wet ingredients to the dry ingredients and, using a rubber spatula, mix all the ingredients thoroughly but do not overmix.
Lastly, fold in the diced peaches and mix.Leave the batter on the counter for 10-15 minutes.
1 cup Diced Peaches
Line the muffin pan in every other cavity. Fill up the liners with the batter.
Place about one tablespoon of the streusel on top of the batter and bake it in a 375°F oven for 10 minutes. Then, reduce the temperature to 350°F and bake for another 13-15 minutes, or until a toothpick inserted comes out clean.
Leave them in the pan for 10 minutes to cool, then transfer them to a cooling rack to cool completely.