1. Preheat oven to 350°F (180°C). Line 18 muffin cups.
2. Combine all muffin ingredients in a large mixing bowl. Whisk together until completely smooth.
3. Combine the streusel ingredients in a separate bowl and mix until crumbly.
4. Fill each muffin cup two thirds full with the muffin batter. Top with one heaping teaspoon of streusel crunch. Bake 20–25 minutes, until set.