Pork or Lamb Vindaloo

Name: Pork or Lamb Vindaloo
Ingredients: 1 1/2 tablespoons grainy mustard (preferably Pommery Moutarde de Meaux); 1 1/2 teaspoons ground cumin; 1 1/2 teaspoons ground turmeric; 1/2–1 teaspoon cayenne pepper; 1 teaspoon salt; 1 teaspoon red wine vinegar; 3 tablespoons vegetable oil; 1 small onion (about 4 ounces), peeled and cut into fine half rings; 6 large cloves garlic, peeled and crushed to a pulp; 1 1/4 pounds boned shoulder of pork or lamb, cut into 1-inch cubes; 2/3 cup canned coconut milk, well stirred