For the pancakes: preheat a large griddle or skillet over medium heat. Preheat oven to lowest temperature then turn off. In a large bowl, combine flour, sugar, salt, baking powder and baking soda. In another bowl, whisk together the buttermilk, sour cream, eggs, vanilla and butter. Gently fold the wet ingredients into the dry ingredients until just combined. Let sit for 10 minutes.
While the batter is resting, prepare the turkey sausage patties. Line a baking sheet with parchment paper. Set aside. In a large bowl, combine the ground turkey, rubbed sage, onion powder, salt and maple syrup. Using a 1/4 cup measuring cup, divide the mixture into 9 balls. Flatten each ball into a very thin circle. Set on the parchment and refrigerate.
Spray the griddle or pan with nonstick spray. Ladle pancake batter onto hot griddle using 1/4 cup scoop. Once bubbles appear and edges start to set, flip to cook second side. Remove to a clean plate. Hold a pancake over your turkey sausage patties to ensure they are about the same size. The sausage can be a little bigger since they will shrink when they cook. Make sure the pancakes DO NOT touch the raw turkey.
Place the pancakes in the warm oven to keep warm.
To cook the sausage: add the turkey sausage patties to the griddle or skillet you used to make the pancakes. Cook for 2 to 3 minutes per side, until cooked to 165 degrees F.
Remove pancakes from the oven. Place on pancake on a plate, top with a turkey sausage patty and top with another pancake. Drizzle with maple syrup if desired.