Turn your Instant Pot to the sauté function. Add 1 tbsp olive oil, add 1.5 cups chopped red onion, 1/2 tsp ground cumin, 3/8 tsp salt, and 1/4 tsp hot smoked paprika. Sauté for 8 minutes, stirring.
Add 4 minced garlic cloves, sauté an additional minute. Deglaze onion from the pot by adding the vegetable broth and scraping the sides with a spatula.
Add diced tomatoes, undrained, and vegetable stock. Set to HIGH pressure for 15 minutes. Naturally release pressure for 10 minutes.
Stir in 1/4 cup whole milk. Use an immersion blender to blend the soup to the consistency you like.
Top Instant Pot tomato soup with canned tomatoes with fresh parsley, shaved parmesan cheese, and black pepper.
Serve this comforting soup whenever you're wanting something warm and easy.