Preheat the oven to 180°C/350°F/Gas 4. Line a rimmed baking sheet with a piece of parchment paper or a nonstick baking mat.

Spoon shredded cheddar cheese onto the prepared baking sheet using 1 tablespoon per mound. Lightly spread out, leaving 2-3 inches between each mound. You will be able to bake 6 at a time on a standard baking sheet.

Bake until the cheese rounds are melted in the center and the edges begin to brown. Set aside to cool for 1-2 minutes but do not let harden.

Lift each melted cheese rounds with a spatula and press on the back of an inverted muffin tin to form cups. The cheese will be very pliable while warm.

Allow the cheese to cool and firm up before removing the "cups" from the muffin tins.

While the cheese cups are hardening, add the olive oil to a medium pan over medium heat. Add ground beef and cook for 5-6 minutes, stirring occasionally, until the meat is nicely browned. Drain any excess fat.

Add cumin, smoked paprika, chili powder, and 2 tablespoons of water to the pan and season to taste with salt and pepper. Continue cooking for 1-2 minutes, just until the spices become fragrant, and the meat is nice and juicy. If necessary, add an additional tablespoon of water to obtain the proper consistency.

Fill the cheese cups with taco beef, chopped tomato, scallion, and a teaspoon of sour cream per cup. Squeeze in some lime juice over the top and enjoy!