Preheat the oven to 450.
Pour the tots into a large bowl. Mash and stir the tots until they are all broken apart and crumbled.
Grease a mini muffin tin and place a few heaping tablespoons of the tot mixture into each muffin spot. Press down in the center. Bake for 15 minutes.
Meanwhile add the onion to a frying pan with a little oil. Cook about 5 minutes. Add in the ground beef and cook 10 minutes until lightly browned and fully cooked. Remove from heat and drain excess fat.
Stir in the ketchup and mayo. Allow to cool for 2 minutes. Add in the cheese.
Remove the tot cups from the oven and press down again in the center. This will be when you really form the tots into the cup shape because now that they have heated up a bit they will form the shape better.
Add a heaping tablespoon of the meat mixture into each of the tot cups. Press down to form and add more if needed depending on the size of your muffin tin.
Bake for 15 minutes.
Remove from oven and allow to cool for 5 minutes. Use a butter knife to remove each tot cup from the tray by first running the knife around the cup to be sure it isn’t stuck anywhere, then using it to get under the cup and pop it out.
Place the cups on a platter, top with pickles and ranch, or toppings/sauces of your choice, and serve.