For the gumbo: 

1. Heat a heavy-bottom casserole or cast-iron pot. If using andouille or other smoked meats, sauté briefly with a little oil and allow the fat to render and set aside, about 5-8 minutes.
2. Adjust to medium-high heat and add garlic, sautéing until lightly browned about 3 minutes.
3. Add onions, celery, and peppers; sauté and stir frequently until soft, about 18-20 minutes. Add tomato paste, cayenne, gumbo file, and dried shrimp (if using) and cook for an additional 3-5 minutes.
4. Next, add kale and collards and cook briefly until they start to wilt, about 5-8 minutes. Add stock and bring to a boil. Reduce to a steady simmer and place the lid on the pot with a small gap to allow steam to escape.
5. Braise for 45 minutes to an hour until greens are tender. Stir the roux and gradually add into the stew to thicken as needed: it should be slightly runny and thinly coat the back of a spoon. Add the cooked meats back into the pot and cook for an additional 5 minutes.

For the stock: 

1. Combine all ingredients and bring to a boil; reduce to a low simmer and cook until 1 quart less, about 1 ½-2 hours.
2. Let cool and strain; pick meat from ham and set both aside.
3. There should be about 3 quarts of stock; you can use your preferred alternative stock for the same volume instead of using smoked ham hocks.

For the roux: 

1. Combine flour and butter and cook under medium heat, stirring frequently until golden brown.
2. Remove from heat and allow to carry over cooking until room temperature. Set aside.