In a small bowl, combine the ground turkey, dried sage, garlic powder, sea salt, and black pepper until well incorporated.
Form the seasoned turkey mixture into one large, flat patty that is roughly the same diameter as your intended pancakes.
In a separate mixing bowl, whisk together the egg whites, nonfat Greek yogurt, oat flour, and baking powder until the batter is smooth and free of lumps.
Heat the olive oil in a large non-stick skillet over medium-high heat.
Place the turkey patty in the skillet and cook for 4 to 5 minutes per side until browned and the internal temperature reaches 165 degrees Fahrenheit.
Remove the sausage patty from the skillet and set it aside on a warm plate.
Wipe the skillet clean and return to medium heat; pour the pancake batter into the pan to form two equal-sized circles.
Cook the pancakes for 2 to 3 minutes until bubbles form on the surface, then flip and cook for another 2 minutes until golden brown.
Assemble the sandwich by placing the turkey sausage patty between the two pancakes and drizzling the top with pure maple syrup.