Preheat oven to 375°F (190°C).
Slice the bell peppers in half lengthwise. Remove the seeds and membranes.
Place pepper halves cut-side up in a baking dish. Drizzle lightly with olive oil.
Bake the peppers for 10 minutes to soften slightly.
While peppers bake, heat 1 tsp olive oil in a skillet over medium heat.
Add minced garlic and sauté for 30 seconds until fragrant.
Add spinach and cook for 3–4 minutes until fully wilted.
Remove skillet from heat. Stir in crumbled feta until combined.
Spoon filling into each softened pepper half (about ¼ cup per half).
Bake for 25–30 minutes until peppers are tender and tops are lightly golden.