Prepare keto mug biscuit and allow to cool before slicing. (See recipe above, or use a store-bought biscuit if preferred.)
Cook bacon as desired and set aside to drain on paper towels. Reserve some of bacon fat in pan to cook egg patty.
To prepare scrambled egg patty, whisk eggs in a measuring cup. Spray a pan with cooking spray, as well as the outer band of wide-mouth mason jar lid. Place lid upside-down in pan and pour in whisked egg. Cover pan and allow egg to set, then flip and carefully remove mason jar lid. (Use another spatula to help if needed!)
Place cheese slice on top of warm egg patty, cover pan, and allow to melt.
Assemble breakfast sandwich with microwave keto biscuit, egg, cheese, bacon, avocado, and a dash of sriracha. (Or whichever toppings you like!)