Soak 1 pound dried pinto beansand cook according to package, adding 1½ teaspoons salt AFTER beans are tender.
Meanwhile, combine 1 pound lean ground beef, 2 cloves garlic, minced, 1 large egg, ¼ cup oyster sauce, 1 tablespoon tomato paste, and 1½ teaspoons Worcestershire sauce in a small bowl. Mix it however you can. Hands work best--it's like making meatloaf. Cover with plastic wrap and let it marinate in the refrigerator while the beans cook.
When beans are tender, drain off juice and reserve.
In a separate skillet, brown ground beef mixture, ½ large onion, coarsely chopped, chopped, and 1 small jalapeño pepper, chopped. Drain excess grease.
Combine beans and meat in one pot and start mashing. A fork will work, but a masher or granny fork works faster. An immersion blender works even better. Mash until there are no prominent whole beans but still some texture. Put small batches in a food processor if you don't want lumps. Add reserved liquid until beans are the thickness you like. If they are still too thick, add a little more water.
Season with ½ teaspoon Adobo seasoningand simmer on the stove over low heat for another 30-45 minutes.
Notes
See the section about "Ingredients and Substitutions" in the post for more information about possible substitutions.