Remove stems from mushrooms. Rub oil on both top and underside to coat. Sprinkle with salt and pepper. Place on a foil-lined sheet tray under the broiler for 2 to 3 minutes. Flip and broil 2 to 3 minutes on the other side, until cooked through.
Meanwhile, in a sauté pan over medium heat, add 1 1/2 tablespoons olive oil, vegetables, paprika, thyme, 1/8 teaspoon salt, and 1/8 teaspoon pepper. Cook for 8 to 10 minutes until cooked through. Add garlic and cook for an additional 30 seconds. Once finished cooking, remove from heat and cover to keep warm.
Add an even amount of vegetable mixture to each mushroom and serve.