Over medium heat in a medium saucepan, heat the butter until melted. Then reduce the heat to low and slowly whisk in the flour to create a roux. Continue to cook until the butter has been absorbed into the flour and is a smooth consistency.
Once the roux has cooked, return the mixture to medium-high heat. Add the stock and allow to simmer, whisking throughout the cooking process. Once simmered and thickened, 8 to 10 minutes, add the pork, chiles, spice and parsley. Allow this to cook for an additional 20 minutes, with reduced heat to medium-low. Finally, add the tomatoes and cook for a final 10 minutes. Taste and adjust spice to preference.