Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly oil it. Rinse bell peppers, slice off the tops, remove seeds and membranes, and halve lengthwise. Pat dry with a towel.

Season peppers

Place pepper halves cut-side up on the prepared baking sheet. Brush or drizzle the 2 tbs olive oil evenly over the peppers and sprinkle with 1 tsp kosher salt and 1/2 tsp freshly ground black pepper. Set aside while you prepare the filling.

Filling (optional)

Cook aromatics

Heat a nonstick skillet over medium heat. Add 1 tbs olive oil (from the prepared amount if desired) and sauté 1/2 cup finely chopped onion for 4–5 minutes until translucent. Add 2 minced garlic cloves and cook 30–45 seconds until fragrant; do not let the garlic brown.

Combine filling ingredients

In a bowl, combine 1 cup cooked quinoa or rice, the sautéed onion and garlic, 3/4 cup quartered cherry tomatoes, 1/2 cup crumbled feta, 2 tbs chopped fresh basil, and 2 tbs toasted pine nuts. Add 1 tsp lemon juice, 1/2 tsp salt and 1/4 tsp black pepper. Taste and adjust seasoning.

Stuff peppers

Spoon the filling evenly into each pepper half, pressing lightly so the filling sits level with the pepper edges. If you prefer a lighter version, leave peppers unstuffed and roast as a side instead.

Bake & Finish

Place the filled (or simply seasoned) peppers in the preheated oven and roast for 22–28 minutes, until peppers are tender and the filling is heated through. If using parmesan, sprinkle 1/4 cup grated parmesan over peppers about 5 minutes before the end of baking to melt and brown lightly.

Remove the peppers from the oven. Drizzle each with 1 tsp extra-virgin olive oil, sprinkle with 1 tbs chopped fresh parsley, and serve warm. Leftovers keep in an airtight container for up to 3 days in the refrigerator.