Prepare the Sweet Potatoes
Preheat your oven to 400°F (200°C). Scrub the sweet potatoes thoroughly and pat dry. Using a fork, pierce each potato 4–5 times to allow steam to escape during the roasting process.
Roast Until Tender
Place the potatoes on a parchment-lined baking sheet. Lightly rub the skins with 1 tablespoon of olive oil and a pinch of salt. Bake for 45–60 minutes. They are done when a knife slides easily into the thickest part of the potato.
Sauté the Mushroom & Garlic Base
While the potatoes are in their final 10 minutes of baking, heat the remaining 1 tablespoon of olive oil in a large skillet over medium heat. Add the sliced mushrooms and cook for 5–7 minutes until golden brown and the moisture has evaporated.
Wilt the Spinach
Add the minced garlic to the skillet and sauté for 30 seconds until fragrant. Add the fresh spinach in batches, tossing gently until just wilted (about 1–2 minutes). Season the mixture with salt and pepper, then remove from heat.
Slice and Fluff
Carefully slice each hot sweet potato down the center lengthwise. Use a fork to gently mash and fluff the orange interior, creating a small "well" or pocket for the filling.
Stuff and Serve
Divide the sautéed spinach and mushroom mixture evenly among the four potatoes. Top each with the diced avocado and crumbled feta cheese. Finish with a final drizzle of olive oil or a sprinkle of fresh herbs if desired. Serve immediately while warm.