Cut the onion, green bell pepper, and celery into uniform small cubes.
Finely chop the garlic and prepare all measured ingredients.
Heat vegetable oil in a heavy pot over medium-low heat.
Gradually add flour while stirring constantly for 20-30 minutes until reaching a dark chocolate color.
Add the Cajun Trinity (onion, pepper, and celery) to the roux and cook for 5-7 minutes.
Incorporate the chopped garlic and cook for 1 additional minute.
Gradually pour in hot chicken broth while stirring constantly.
Add bay leaves, chopped jalapeño pepper, and salt.
Add sliced andouille sausage and chicken pieces, cooking on low heat for 45 minutes.
Incorporate sliced okra and cook for 10 minutes.
Add cleaned shrimp in the last 10 minutes of cooking.
While the gumbo rests, prepare white rice according to package instructions.
Remove from heat and let rest for 20-30 minutes before serving.