In a small bowl, combine the grass-fed ghee, garlic powder, and dried oregano until smooth.
Spread a thin, even layer of the seasoned ghee onto one side of each of the three bread slices.
Place a large non-stick skillet over medium-low heat to ensure even melting without burning the bread.
Place the first slice of bread into the skillet, ghee-side down. Layer with half of the sliced turkey and half of the sharp cheddar.
Place the second slice of bread on top of the cheese, ghee-side down. Layer with the remaining turkey and the rest of the cheddar.
Place the third slice of bread on top of the stack, this time with the ghee-side facing up.
Cover the skillet with a lid for 2 to 3 minutes; this traps heat to melt the cheese thoroughly through the thick layers.
Carefully flip the entire triple-decker sandwich using a wide spatula and cook for another 2 to 3 minutes until the bottom is toasted.
During the final minute, sprinkle the grated parmesan directly onto the hot crust and flip once more for 30 seconds to create a salty, crispy cheese frico.
Remove from the pan, let it rest for one minute to set the layers, and slice diagonally with a serrated knife.