Preheat the oven to 400°F (200°C).

Wash and halve the sweet potatoes lengthwise, brush with olive oil and sprinkle with salt. Roast cut-side down on a baking sheet for 35-45 minutes until tender.

Heat olive oil in a skillet over medium heat. Sauté diced onions and bell peppers for 5-7 minutes until soft.

Add your chosen protein to the skillet and cook until fully cooked, around 8-10 minutes. Add garlic, cumin, and chili powder during the last minutes.

Stir in fresh spinach and cook for 2-3 minutes until wilted.

Remove sweet potatoes from the oven, let cool, then scoop out flesh to create cavities. Mix scooped flesh into protein filling.

Fill each sweet potato half with the protein mixture and sprinkle with cheese if desired. Bake for another 10 minutes.

Let cool for a few minutes, then garnish with cilantro, green onions, or crumbled feta before serving.