Heat the oil in a large stockpot over medium-high heat. Sear the oxtail on all sides until browned, about 3-4 minutes per side. Remove the oxtail and set aside.
Step 2: Build the Pho Broth
In the same stockpot, add the quartered onion and halved garlic. Sauté until fragrant, about 2 minutes.
Return the seared oxtail to the pot and add beef broth, water, bay leaves, fish sauce, soy sauce, and sugar.
Bring to a boil, then reduce the heat to a simmer. Skim off any impurities. Simmer gently for 2-3 hours, or until the oxtail is tender and falling off the bone.
Strain the broth to remove solids and set aside. Keep the broth warm.
Step 3: Prepare the Gumbo Base
In a Dutch oven, heat the oil over medium-high heat. Add the flour and whisk continuously to create a roux. Cook until the roux reaches a dark chocolate color, about 20-30 minutes, stirring frequently.
Add the diced bell pepper, celery, and onion to the roux. Cook until the onion becomes translucent, about 5-7 minutes.
Stir in the minced garlic and cook for 1 minute, being careful not to burn it.
Pour in the beer and cook for 2-3 minutes, allowing the alcohol to cook off.
Gradually ladle the pho broth into the roux mixture, whisking to combine smoothly. Add the oxtail pieces back to the pot.
Stir in Uncle Dibbz King Creole Blend, then add the sausage. Bring the gumbo to a gentle boil, then reduce the heat to low and simmer for 3 hours, stirring every 15 minutes.
Step 4: Assemble the Dish
Ladle the gumbo into a bowl.
Top with a scoop of cooked rice and garnish with green onions, cilantro, lime wedges, and sliced jalapeños.