1. Cream together margarine and sugar.
2. Add eggs one at a time, then mashed bananas.
3. Add baking soda/water mix and the vanilla, then combine.
4. Mix flour and cinnamon in a separate bowl, then add to banana mix and combine.

Make the muffins, one of two ways:

1. If you want a Nutella centre, fill your muffin cups about a 1/4 full, then add about a teaspoon of Nutella into the centre. Top off the muffin cup with more batter, to make the muffin cups about 1/2 full in total.
2. Or if you just want regular banana muffins, fill the muffin cup about 3/4 full.
3. Bake for 15-20 minutes in a 350 degree oven.