Chocolate Chip Banana Crumb Muffins

I found this recipe for crumb-topped banana muffins on the internet when John's family was visiting. I altered them slightly (adding chocolate chips, extra banana, and a bit of oil), and they ended up being the moistest, most delicious banana muffins I've ever had. I'm not the only one who raved like a maniac over them, either, which is the assurance I needed to post the recipe. (Next time, I may try substitutingf applesauce for some of the butter/oil, but only if I'm feeling annoyingly health-conscious.)

As with all banana recipes, the darker the bananas you use, the more delicious and pronounced their flavor will be in the recipe.

• 1 and 1/2 cups all-purpose flour
• 1 teaspoon baking soda
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 3 overly ripe bananas, mashed (I used nearly four)
  
• 3/4 cup white sugar
• 1 egg, lightly beaten
• 1/3 cup butter, melted (I also added 2 or three tablespoons of canola oil)
• 1 cup chocolate chips
  
• 1/3 cup packed brown sugar
• 2 tablespoons all-purpose flour
• 1/8 teaspoon ground cinnamon
• 1 tablespoon butter

1. Preheat oven to 375 degrees F (190 degrees C). Lightly grease 10 muffin cups, or line with muffin papers. (***My batter ended up making about 14 muffins.)
   
2. In a large bowl, mix together 1 1/2 cups flour, baking soda, baking powder and salt. In another bowl, beat together bananas, sugar, egg and melted butter, oil, and chocolate chips. Stir the banana mixture into the flour mixture just until moistened. Spoon batter into prepared muffin cups.
3. In a small bowl, mix together brown sugar, 2 tablespoons flour and cinnamon. Cut in 1 tablespoon butter until mixture resembles coarse cornmeal. Sprinkle topping over muffins.
4. Bake in preheated oven for 18 to 20 minutes, until a toothpick inserted into center of a muffin comes out clean.

* I also added a touch of cinnamon to the muffin batter.