Crab Peri Peri

Ingredients

• 1 teaspoon dried red chili pepper flakes
• 3 garlic cloves, chopped
• 1/2 teaspoon garam masala
• 1/2 teaspoon cumin seed
• 1 tablespoon ginger, grated
• 2 large tomatoes, skins removed
• 1/3 cup cider vinegar
• 1/2 teaspoon salt (or to taste)
• 2 teaspoons vegetable oil
• 1 small red onion, chopped fine
• 4 blue crabs, cleaned and chopped into quarters with the shells on