Preheat oven to 325.
In a food processor, process the onion until completely broken down.
Add bacon and process again until the bacon is mixed with the onion.
Add burger (or lamb) and spices and process for about two minutes, until everything is completely mixed. (It will look like a paste of sorts.)
Divide meat mixture between two loaf pans.
Place loaf pans into a 9x13 dish and fill dish halfway with water. (This creates a water bath for the meat mixture.)
Bake for 60 minutes, or until internal temperature reaches 165 degrees.
As soon as you remove the meat from the oven, cover with a bit of parchment paper, and set something heavy on top of the meat (think cans of vegetables, glass jars of peanut butter . . . ).
Let rest for 30 minutes, then move to the refrigerator and refrigerate for 45 minutes to an hour.
Place chilled gyro meat on a cutting board and slice as thinly as possible.
Place 1 - 2 Tablespoons of coconut oil in a skillet and heat over medium heat. Fry gyro meat in hot oil until browned and a bit crispy around the edges, flipping meat part way through. (This only takes a moment or two.)
Remove meat from skillet and drain on paper towels.
Continue frying meat in batches, adding more coconut oil as needed.