1 can black beans
1 clove garlic (optional)
Drain beans, reserving 1/2 cup liquid.
Heat small pot with oil and (if using) cook garlic briefly.
Add beans and cook on medium-high for 2-3 minutes.
Add reserved liquid and simmer 2-5 minutes.
Reduce heat to low and stir in 1-2 tbsp butter.
Remove heat, mash beans, and season with salt & pepper.