"Keto Burger Fat Bombs from Delish.com have your lifestyle in mind...."
Cooking spray, for muffin tin
ground beef
garlic powder
Kosher salt
Freshly ground black pepper
cold butter, cut into 20 pieces
(8-oz.) blcok cheddar cheese, cut into 20 pieces
Lettuce leaves, for serving
Thinly sliced tomatoes, for serving
Mustard, for serving