Sweet bean burritos

I found this burrito recipe in my Saving dinner book.  I think half of the time I try something because it sounds different and I can't decide if it will taste good.  Then I'm apprehensive to actually taste what I've made.  This would be one of those meals.  Sweet potato with black bean?  I would have never thought to stick those two together.
Unfortunately for me, I can't remember how much we liked them, or exactly how much spices I added.  I do remember that they were better than I expected.  The sweet potato did make them sweet, but it was still good.  Went well with the cumin.

Ingredients

• 1-2 Tablespoons butter
• 1/2 cup onion, diced
• 3 cloves garlic, pressed (I may have just used garlic powder - I can't remember)
• 2 cans black beans, rinsed and drained
• 2 medium sweet potatoes, cooked and mashed (I made these in the microwave to make them quick and easy - had them cooking while sauteeing my onions)
• 1 teaspoon cumin (I may have added more)
• cheddar cheese
• tortillas

Directions

1. In a skillet, saute onions in butter until soft and fragrant.  Add garlic and saute an additional minute.  
2. Add the beans, mashed sweet potatoes and cumin and mix well.
3. Heat tortillas.  Put bean mixture and cheese in each burrito and roll up.