Ingredients 1 cup canola oil 3 large yellow onions, thinly sliced 2 tbsp. garam masala 1 tsp. crushed red chile flakes 1⁄2 tsp. turmeric 18 black peppercorns 9 pods green cardamom 3 pods black cardamom 2 sticks (2") cinnamon 6 cloves garlic, minced 6 tomatoes, cored and minced 5 serrano chiles, stemmed and minced 1 (1 1/2") piece ginger, peeled and minced 2 lb. trimmed lamb shoulder, cut into 2–3"