Filling

Make a roux by combining 3 tablespoons vegetable oil with the flour in a medium heavy skillet. Cook over medium-low heat, stirring about every 4 to 5 minutes, until dark mahogany in color, about 45 minutes to 1 hour. Do not allow roux to burn.

Meanwhile, heat 2 tablespoons butter with 1 teaspoon vegetable oil in a Dutch oven over medium heat. Saute the sausage slices until well browned on both sides. Transfer to a plate with a slotted spoon. Add the ham strip and saute until lightly browned; transfer to the plate with sausage slices.

Add the remaining butter to the pot and stir in the onion, scraping the bottom and sides of the pot with a wooden spoon. Cook over medium heat, stirring constantly for 2 minutes until onion is translucent. Reduce heat to medium-low and add the garlic, bell peppers, celery and rice. Cook 5 minutes more.

When the roux is finished, add to the vegetable/rice mixture and stir in the chicken stock. Heat to boiling and add the reserved sausages and ham, reduce the heat. Cook covered over medium-low heat for 25 minutes. Stir in the cayenne pepper, salt and black pepper to taste, the shrimp and okra. Cook, stirring gently for 2 ro 3 minutes. Remove from heat.

Biscuit Topping

Preheat the oven to 450˚F.

Combine the flour with the sugar, baking powder, baking soda and salt in a large bowl. Cut in the cold butter with a knife. Blend with a large fork until mixture has the texture of coarse crumbs. Using a wooden spoon, stir in the buttermilk and work into a soft dough. Roll out the dough about 1/2-inch thick on a floured board and cut into 12, 2 1/2-inch rounds.

To Finish

Transfer the hot gumbo filling to a 2-inch deep, 9-inch round baking dish. Place the cut biscuit dough over the top. Brush the dough with the melted butter. Bake until the biscuits are puffed and golden brown, about 20 minutes.

Serve immediately.