Prep the eggplant: Cut the eggplant into even cubes.
If your eggplant seems seedy or you’re sensitive to bitterness, sprinkle with salt and let it sit in a colander for 15–20 minutes. Pat dry. This step helps it brown better and stay tender.
Brown the sausage: Heat a large skillet over medium-high.
Add sausage and break it up with a spatula. Cook until browned and slightly crisp at the edges, 6–8 minutes. Transfer to a plate, leaving some fat in the pan.
Sauté the aromatics: Add 1 tablespoon olive oil if the pan looks dry.
Toss in the onion and bell pepper. Cook, stirring, until softened and lightly golden, 4–5 minutes. Add the garlic and cook 30 seconds until fragrant.
Cook the eggplant: Add the remaining olive oil and the eggplant cubes.
Season with a pinch of salt and pepper. Cook 6–8 minutes, stirring occasionally, until the eggplant starts to brown and soften. If it drinks up the oil, add a small splash more.
Season the skillet: Sprinkle in oregano, red pepper flakes, and smoked paprika.
Stir to coat the vegetables so the spices can bloom and deepen in flavor.
Deglaze and simmer: Pour in the marinara and chicken broth. Scrape up any browned bits. Return the sausage to the pan and stir.
Lower heat to medium, cover, and simmer 5–7 minutes until the eggplant is silky and the flavors meld.
Finish and adjust: Remove the lid. If using spinach or olives, fold them in now and cook 1–2 minutes. Stir in the Parmesan until it melts and lightly thickens the sauce.
Taste and adjust salt and pepper.
Garnish and serve: Sprinkle with fresh parsley or basil. Add extra Parmesan if you like. Serve straight from the skillet while hot.