Heat 2 tablespoons of neutral oil in a large frying pan over medium-high heat
Cook diced onions until golden brown, stirring occasionally
Add garlic, ginger, serrano peppers, and tomato paste; cook for 2-3 minutes
Add spice blend (curry powder, coriander, cinnamon, turmeric, nutmeg, salt, pepper, sugar) and toast in the oil for 1-2 minutes
Add crushed tomatoes and cook for 4-5 minutes, using tomato juices to deglaze the pan
Cool the flavor bomb to room temperature
Divide into equal portions and freeze in silicone ice cube trays or freezer-safe containers
Once frozen, transfer to freezer bags and label
Store in freezer for up to 3 months
