Place 2 tablespoons oil in a multicooker. Heat on sauté mode until hot. Add onion, bell pepper and garlic; cook, stirring often, until starting to soften, 2 to 3 minutes. Add cabbage, cauliflower, carrots and green beans and continue cooking, stirring often, until starting to soften, 4 to 6 minutes more. Add broth, tomatoes, bay leaf and salt. Turn off heat. Close and lock the lid. Cook at high pressure for 5 minutes.
Release the pressure. Remove bay leaf, then stir in spinach, beans and basil. Serve with a drizzle of oil, if desired.
