Preheat oven to 400° + line a sheet pan with foil

Wipe 2 mushrooms with a damp paper towel; remove stems + using a spoon, scoop out the dark gills; place on sheet pan bottom-side up, season with salt/pep + drizzle with oil; bake 10 min

Meanwhile, heat 1 tbsp oil in skillet over med-high + sauté pepper mix with salt/pep 4-5 min or until soft + starting to brown; add ½ bag of spinach + sauté 2-3 min until wilted

Remove mushrooms from oven, flip + fill with veggies; drizzle stuffed mushrooms with ½ pouch sauce; bake 7-9 min until hot + bubbling