This copycat recipe comes from Matt's El Rancho in Austin, TX via The Austin Cookbook. It is a Tex-Mex Queso Classic.
Heat skillet over medium heat and add all ingredients. Cook, stirring, until the onion is translucent and the meat is cooked, about five minutes. Most of the liquid should evaporate, but the mixture shouldn't be dry. Keep warm while you prepare the other components.
Combine the avocados, lemon juice, garlic, and oil, mashing everything slightly. The mixture should be chunky, not smooth. Stir in the tomato and season with salt.
Bring 1 Cup of water to boil in a small saucepan. Add the celery, bell pepper, onion, poblano, and tomato and boil briefly to cook everything, about one minute. Turn the heat down to low and gradually whisk in the cheese. Heat for a few minutes, stirring constantly. The second all the cheese is melted and everything is heat through and smooth, remove from the heat so it doesn't overcook. Do this step right before serving.
Pour the hot queso into a wide, shallow serving bowl. Add a scoop of meat and a scoop of guacamole, about 1/2 cup each. Do not mix. Guests should combine the queso, guacamole, and ground beef together with tortilla chips as they eat it.