Heat a large frying pan over medium. Add 1 tbsp oil, then 1 chopped onion. Cook until soft, about 3 min. Stir in a drained 796ml can diced tomatoes, 2 minced garlic cloves, 1/2 tsp each thyme and red pepper flakes. Cook about 5 min. Stir in 2 tbsp peanut butter and 1/4 tsp salt. Add a 227 g pkg fresh spinach, coarsley chopped. Cook until wilted.