Heat the ½ cup aceite vegetal in a large Dutch oven or heavy-bottomed pot over medium heat. Once shimmering, whisk in the ½ cup harina para todo uso until smooth. Switch to a wooden spoon or heat-safe spatula.

Cook the roux, stirring constantly and scraping the bottom of the pot, for 25–35 minutes. You're aiming for a deep chocolate-brown color — like dark milk chocolate or a copper penny. Don't rush this step and don't walk away. If it smells burnt, reduce the heat.

Once the roux is dark and fragrant, immediately add the diced cebolla amarilla, 1 pimiento verde, and 3 tallos de apio. The vegetables will sizzle dramatically — this is normal. Stir vigorously to coat everything in the roux and stop the cooking. Cook, stirring frequently, for 6–8 minutes until the vegetables soften.

Add the minced dientes de ajo and cook for 1 more minute, stirring constantly, until fragrant.

Add the sliced salchicha andouille to the pot and stir to combine. Cook for 3–4 minutes to lightly brown the sausage and render some of its fat into the base.

Add the 1 ½ lb muslos de pollo sin hueso ni piel, all of the spice blend ingredients (2 tsp condimento cajún, 1 tsp pimentón, 1 tsp tomillo seco, 1 tsp orégano seco, ½ tsp pimienta negra, ¼ tsp pimienta de cayena agregue más, 2 tsp sal kosher más, 2 tsp salsa Worcestershire, and 2 pieces hojas de laurel), and stir well to coat everything evenly.

Pour in the 6 cups caldo de pollo bajo en sodio preferido and add the 1 lata tomates with their juices. Stir well, scraping up any bits from the bottom of the pot. Bring to a boil over high heat, then reduce to a gentle simmer.

Simmer uncovered for 40–45 minutes, stirring occasionally, until the 1 ½ lb muslos de pollo sin hueso ni piel are very tender and the gumbo has thickened and deepened in flavor. Skim any excess fat or foam from the surface as needed.

Stir in the 1 ½ cups okra congelada rebanada and cook for 10 minutes. The 1 ½ cups okra congelada rebanada adds both flavor and natural thickening to the gumbo.

Add the 1 lb camarones grandes pelados y and stir to submerge. Cook for 3–5 minutes, just until the 1 lb camarones grandes pelados y are pink and cooked through. Do not overcook. Remove and discard the 2 pieces hojas de laurel. Taste and adjust 2 tsp sal kosher más, ½ tsp pimienta negra, and ¼ tsp pimienta de cayena agregue más as needed.

To serve, place a scoop of cooked 4 cups arroz blanco de grano largo in the center of a wide, shallow mixing bowl. Ladle the gumbo generously around and over the 4 cups arroz blanco de grano largo. Garnish with sliced tallos cebollas verdes, fresh perejil fresco picado, and a small pinch of polvo de filé para espesar y dar sabor if using. Serve immediately.