morning cajun tomato gravy

Growing up, my mom used to make a version of this gravy. She'd just call it tomato gravy. Apparently, it is an old country classic. 
It doesn't get cooked much in my house because my husband is a white gravy type of man.  I'm okay with white gravy, but find the tomato one is more flavorful! 
You know you hit southern country when you start your cooking process with salt meat. 

Ingredients: 
5 slices of salt pork
1 can 28oz whole peeled tomatoes
1/4 cup grease reserved from cooking down the salt pork
1/4 cup flour
1/4 cup diced onion
1 cup water
1 tsp Cajun seasoning
1/2 tsp salt
1 tsp black pepper
Directions: 
Heat skillet on medium high
Add salt pork to skillet and cook down until browned
Reserve 1/4 cup of grease that comes off the pork, if you do not have 1/4 cup, just add canola oil or oil of choice
Add flour to the hot oil and make a roux
Keep stirring it until it is a light peanut butter colored, no need for a dark roux
Add the onions and stir until they are glossy
Add seasonings
Add the can of tomatoes and water
Allow to simmer for at least 15 minutes
Serve over warm buttermilk biscuits