Preheat your oven to 375°F (190°C) and coat a medium-sized baking dish with cooking spray or olive oil to prevent sticking.

Bring a large pot of salted water to a boil. Add sweet potato slices and parboil for about 8 minutes. Drain and set aside.

In a large skillet, heat olive oil and cook spicy sausage for approximately 8 minutes until browned and cooked through. Set aside.

Toss the sliced apples with cinnamon, salt, and pepper, and drizzle with olive oil.

Layer half of the parboiled sweet potatoes in the baking dish, followed by half of the cooked sausage, half of the seasoned apples, and a sprinkle of pecans. Repeat layers.

Top with shredded cheddar cheese and remaining pecans. Cover with foil and bake for 30-35 minutes until bubbly.

Remove foil during the last 5 minutes to brown the cheese. Keep an eye on it to prevent over-browning.

Let the casserole rest for 5 minutes before serving.