Wash and dry all produce. Halve, peel, and finely chop onion. Thinly slice mushrooms and garlic. Thinly slice sausage into rounds.

Heat a drizzle of olive oil in a medium pot over medium-high heat. Add sausage to the pot and sear until browned, 1-2 minutes per side.

Add mushrooms, onion, and half the garlic to pot and cook until softened, 3-4 minutes, tossing.

Add oregano, 11/2 cups water, and stock concentrate to pot. Bring to a simmer and stir in couscous. Let simmer uncovered until couscous is al dente, about 15 minutes. TIP: Add a splash of water if couscous absorbs all liquid before al dente.

Heat a drizzle of olive oil in a medium pan over medium heat. Toss in remaining garlic and cook until fragrant, 30 seconds. Add spinach and toss until wilted, 3-4 minutes, until wilted. Season with salt and pepper.

Stir Parmesan into couscous to melt. Divide couscous between bowls and top with the spinach.