Chicken and Andouille Gumbo

1/4 cup vegetable oil

1/4 cup flour 

1 large yellow onion, diced

1 green bell pepper, diced

4 stalks celery, diced

2 teaspoons dried thyme

1 teaspoon dried oregano

1/2 teaspoon cayenne

1 (28-ounce) can crushed tomatoes

2 pounds boneless skinless chicken thighs, trimmed and cut into 1-inch pieces

4 cups chicken stock

12 ounces andouille, thinly sliced

1 (10-ounce) package frozen okra or 2 heaping cups sliced blanched fresh okra

Juice of 1 lemon

Salt and pepper

Cooked rice, for serving

In a Dutch oven over medium heat, whisk together the oil and flour until smooth. Cook, stirring, until the mixture is the color of milk chocolate. Stir in the onion, bell pepper and celery, and cook until soft, about 4 minutes. Add the spices and stir until aromatic, about 30 seconds. Stir in the tomatoes, then add the chicken, then the stock. Simmer until chicken is cooked through and the liquid is reduced, about 20 minutes. Add the andouille and okra, and let simmer until the liquid is thick, about 15 minutes more. Season with lemon juice and salt and pepper. Serve over rice.