Drain 1700g of canned pinto beans, keeping the liquid.
Heat 3 tablespoons of olive oil in a large skillet over medium-high heat. Cook ½ finely diced yellow onion, 3 minced garlic cloves, 1 finely diced jalapeño, and ½ teaspoon of dried Mexican oregano for 5 minutes, stirring.
Add the beans and cook for 2 minutes. Add enough reserved liquid to loosen them, then mash until as smooth as you like.
Stir over low heat until hot and creamy, adding more liquid if needed. Season with salt.
