Preheat oven to 350°F (175°C).

In a large bowl, cream together the butter-flavored shortening and sugar until light and fluffy.

Beat in the eggs one at a time.

Stir in the mashed ripe bananas, milk, and vanilla extract.

In a separate bowl, combine the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients and mix well.

Stir in the chopped nuts.

Fill paper-lined muffin cups two-thirds full.

Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Cool in the muffin pan for 5 minutes before transferring to a wire rack to cool completely.