Ingredients:
* large roast
* 1/2 cup oil (less is okay)
* 2 med. sliced onions
* large can (gallon size) of stewing tomatoes
* 3 tbsp. flour
* salt
* pepper
* bread
Saute onion in hot oil in a sauce pan. Remove onions and place into roasting pan for an oven. Rinse the roast, then dry and rub salt and pepper onto all sides. Sear in hot oil left from the onions, then place oil and roast into roasting pan. Add the entire can of tomatoes and juice (from the can) to the roasting pan. Ingredients should almost cover the roast. More can be exposed, but there needs to be a lot of liquid for the gravy.
Roast the meat in a preheated at 350 degrees for 2.5 to 3 hours. Use a meat thermometer to ensure proper cooking (rare, medium rare, etc.). Once done, remove the roast from the pan and put on a platter. Slice for eating.
Take flour, mix with a small amount of cold water (just enough to make a thick gravy) and then add to the tomato sauce left in the roasting pan. Heat and stir until thickened (might be easier to move to a sauce pan).
Serve by placing a thick piece of bread on your plate, a slice of roast beef on the bread, and lots of tomato gravy over the bread/meat. It taste better the next day.
It could be eaten with mashed potatoes, but then it wouldn't be TEXAS roast beef.
My wife has it the way you mentioned. The tomato gravy is excellent on bread or mashed potatoes. But it's a little different. And the slices of bread should be real thick (homemade is the best). They call it "Texas toast" here (about twice as thick as a normal slice of bread).
My wife also puts on garlic. Wouldn't make my grandma very happy knowing that my wife messed the recipe up like that. But I must admit, it is very good that way as well.