Heat olive oil in a large skillet over medium heat.
Add onions and cook 3–4 minutes until softened.
Add garlic, mushrooms, zucchini, bell pepper, and carrot.
Sauté until vegetables release moisture and cook down (8–10 minutes).
Add spinach/kale and cook until wilted.
Season with smoked paprika, oregano, basil, red pepper flakes, salt, pepper, and fennel seeds if using. Pro tip: rub your herbs and seeds in your hands as you add them. The warmth releases natural oils and heightens flavor.
Cook another 2–3 minutes, then set aside.