https://keviniscooking.com/authentic-refried-beans/

1 lb pinto beans (See Note 1)
1 white or yellow onion
1 guajillo chili pepper (or Ancho, stem and seeds removed)
1 large garlic clove crushed only
1/4 cup lard (See Note 2)

1. Add beans to pot, cover with 2inches water. Add chili powder and quarter onion and crushed garlic
2. Bring to boil, reduce heat to simmer, simmer 1.5-2 hours covered
3. Remove onion chili and garlic
4. Drain, save liquid
5. Melt lard in pot
6. Add beans to pot, fry for several minutes
7. Mash beans, add liquid to desired consistency