Preheat your oven to 375 degrees Fahrenheit.
In a medium mixing bowl, combine your dry ingredients. Then add your wet ingredients and mix until well combined.
In a small bowl, mix together your streusel topping, breaking everything up with your fingers so there are no large clumps left and the mixture is crumbly.
Transfer your batter evenly into the muffin cups in your tin, then sprinkle ~1 tablespoon of streusel topping per muffin over the top and pat the topping down evenly.
Bake for 24-32 minutes, or until a toothpick comes out of the center of a middle muffin clean.
Remove from the oven and let the pan cool completely before removing the muffins. You may need to use a knife around the edges to make sure nothing has stuck.
Eat right away or store to eat throughout the week.
Enjoy!