Wash and dry the bell peppers. Seed them and slice into 1/2-inch strips. Halve and thinly slice the sweet onion. Thinly slice or mince the garlic. Try to keep the slices relatively even so the peppers and onions cook at a similar rate.

Place a large, heavy skillet (cast iron or stainless steel) over medium heat. Add 2 tablespoons of the olive oil and heat until it shimmers.

Add the sliced onion to the skillet and cook for 3–4 minutes, stirring occasionally, until it begins to soften and turn translucent. Sprinkle with a small pinch of salt to help it release moisture and sweeten.

Add all of the sliced bell peppers to the skillet along with the remaining 1 tablespoon olive oil. Toss gently so the peppers and onions are coated in oil. Cook for 10–12 minutes, stirring every couple of minutes, until the peppers begin to soften and develop golden brown spots. If the pan looks dry or the peppers start sticking, add a tiny bit more oil or a splash of water.

Stir in the garlic, 1 teaspoon kosher salt, black pepper, Italian seasoning, smoked paprika, and red pepper flakes if using. Cook for 2–3 minutes, stirring often, until the garlic is fragrant and lightly golden but not browned.

Reduce the heat to medium-low and cook for another 8–10 minutes, stirring occasionally, until the peppers are very tender, glossy, and just starting to caramelize around the edges.

Turn off the heat and stir in the balsamic vinegar, scraping the bottom of the pan to release any browned bits. Taste and adjust seasoning with more salt or pepper if needed. Sprinkle with chopped fresh parsley or basil.

For a heartier main, stir in the chickpeas while the skillet is still warm and let them heat through for a few minutes. Finish with crumbled feta or goat cheese. Serve over cooked quinoa, couscous, or brown rice if desired.