Heat a little olive oil in a pan and once hot fry your pinto beans and mash them with a potato masher. Add a little water if necessary. (I cook my beans with onion, garlic and salt so they are already seasoned. If yours are not or if you used canned, make sure they are tasty by adding salt and maybe some garlic powder)
Once mashed lay out in a 7" by 9" (19x23cm) glass dish (or bigger) and wait for the beans to cool down a little.
Add sour cream on top of beans.
Peel avocado and cut in about 1/4" (0.5cm) slices and lay out on top of sour cream. Salt and Pepper a little.
Peel and chop onion and peel and crush garlic (wash, deseed and chop jalapeño pepper, if using).
Heat a little olive oil over medium heat in a pan and once hot fry onions and garlic (and jalapeño pepper if using) until translucent. Then add ground beef and take apart with wooden spoon or rubber spatula so it cooks evenly. Season with cumin, dried coriander (and cayenne if using). Keep moving while the meat fries. Once the meat is cooked lay on top of avocados.
Wash, cut and deseed tomatoes. (Deseeding is important otherwise the liquid will drip down to the sour cream and together with the meat juice liquify it too much). Cut into 1/2" (1cm) dice and lay on top of meat.
Grate cheese and lay on top of tomatoes.
Wash and chop fresh coriander and sprinkle on top of cheese.