Bring a pot of water to a boil & prepare the orecchiette pasta according to package directions. When it is cooked, drain it well, drizzle it with the remaining Tbsp of olive oil. Shake it around a bit in the strainer to keep pieces from getting stuck together.
Heat the milk & applesauce in pot that was used to cook pasta, stirring constantly. Do not bring to a boil.
In a Dutch oven over medium heat, melt butter & whisk in the flour. Cook mixture for two minutes, whisking all the while then whisk in the hot milk/applesauce mixture. Cook for 2 more minutes continuing to whisk while the mixture is thickening.
Remove the Dutch oven from the heat & stir in salt, pepper, sage, gruyere (save a bit for garnish if you wish), cheddar, onion & sausage slices. Combine evenly then add cooked pasta & stir until pasta is evenly covered with sauce.
Place the Dutch oven in the oven, uncovered & bake for 30-40 minutes or until the orecchiette on top just begins to turn golden brown at the tips.