This hearty vegetable gumbo is traditionally eaten on Holy Thursday to fortify worshipers for Good Friday, a day of fasting and abstinence from meat. I've seen recipes that contain everything from chicken wings to spicy chaurice sausage (a Cajun cousin of chorizo) to smoked brisket. Custom also dictates that the gumbo is supposed to have an odd number of greens--five or seven or nine and as many as fifteen--for luck. Many recipes include foraged herbs such as peppergrass, as well as the green tops from radishes, carrots, and beets. Leah Chase, the Grande Dame of NOLA, is world famous for her Gumbo Z’herbes. At her restaurant, Dooky Chase, there are three lunch seatings on Holy Thursday, serving nearly five hundred guests. Most recipes are quite the production, featuring multiple pots and pureeing vast quantities of simmered greens. I've streamlined the recipe by using baby greens and prechopped greens to avoid pureeing them at the end. Aim for the odd number in any combination of "z'herbes" you'd like. This amount of liquid is suitable for 3 pounds of greens.
Heat 1 tablespoon of the oil in a large heavy pot over medium heat. Add both kinds of sausage; cook until the sausage is cooked through and the fat has rendered, about 5 minutes. Use a slotted spoon to transfer the meat to a plate.
Add the remaining 5 tablespoons oil to the pot. Add the flour and cook, stirring frequently with a wooden spoon, until deep golden brown, about 15 minutes. Add the onion, poblano, and celery and cook, stirring often, until onion is translucent, 3 to 5 minutes. Add the garlic and cook until fragrant, 45 to 60 seconds. Add the stock and stir to combine.
Plop the ham hock in and bring to a boil over high heat. Return the chorizo and andouille to the pot. Add the collard greens, kale, spinach, cabbage, green onions, and thyme. (You may need to let the greens cook a bit between additions so they will all fit in the pot. Don't be tempted to add additional liquid too soon: It's easy to add but hard to remove, and you want the gumbo to be dense and like stew, not soup.) Reduce the heat to maintain a simmer. Cook until the greens are tender, about 45 minutes. Taste and adjust for seasoning with salt and pepper. Add hot sauce to taste. Serve ladled over cooked white rice with hot sauce on the side.