Shredded beef is sandwiched between two crispy fried corn tortillas with plenty of refried beans and cheese. It's topped off with a fresh avocado salsa.
Pour oil into a heavy skillet to cover the bottom of the pan with about 1/2 to 1-inch of oil. Heat to 350 degrees.
Working 1 or 2 at a time, fry tortillas for about 60 seconds per side until crisp and golden. Transfer to a paper towel-lined baking sheet to drain.
Preheat oven to 350 degrees.
Spread some refried beans on top of one of the cooked tortillas. Top with a pinch of mozzarella cheese, some shredded beef, and then more cheese. Top with another tortilla like a sandwich and add another generous pinch of cheese to the top. Place on a baking sheet. Repeat with the remaining tortillas until you have 6 chalupas. Put chalupas in oven for 5 minutes until cheese melts.
Meanwhile, make avocado salsa by combining tomatoes, avocados, onion, cilantro, salt, and lime juice in a bowl.
Serve chalupas immediately with a heaping spoonful of avocado salsa and some sour cream.