Heat oil in large pan on medium heat.
Add shrimp and salt and pepper, sear for about 2 minutes.
Add mushrooms, red onion, garlic and tomatoes.
Flip shrimp and cook about two more minutes. Shrimp should be white throughout.
Add vermouth to deglaze pan. Add basil, spinach, lemon and scallions. Shut off heat. Toss until spinach wilts.