01 -
Preheat the oven to 400°F. Carefully take out the stems from the mushrooms without damaging the caps. Combine balsamic vinegar with 1/4 cup olive oil, stir in a sprinkle of sage and garlic powder. Allow the mushroom caps to soak while you prep everything else.
02 -
Chop up the spinach roughly, tossing out any tough stems. Keep the garlic minced and handy.
03 -
In a pan, add 3 tablespoons of olive oil and let garlic gently brown for around 3 minutes. Pour in chopped spinach and stir occasionally as it wilts for about 5 minutes. Season it lightly with salt and pepper, tasting as you go.
04 -
On a baking tray, arrange the seasoned mushroom caps with the gills touching the sheet. Bake these for 10 minutes.
05 -
Turn the roasted caps over and pour out any collected liquid. Load the centers with the garlic spinach mix and sprinkle the feta cheese (roughly 1.5 tablespoons per cap) on top. Pop the tray back into the oven for another 20 minutes, letting the toppings get nice and bubbly.