Preheat the skillet
First of all, preheat the skillet on medium heat. Make sure that it is completely dry and clean.
Slice the tomatoes
After washing the tomatoes, slice them into small chunks.
Heat the oil
Pour the oil into the pan and heat it for a few minutes. Do not add anything to it until it gets extremely hot.
Start adding the flour to the pan
Once the oil gets heated, start adding the flour to the skittle. Make sure not to add all of it at once. This process should be done slowly and while you do it, continue stir the mixture until it gets thick.
Add milk to the flour
Now, start pouring in the milk into the pan. It should be done in a similar way to what you used while adding flour. Continue whisking the mixture and allow it to cook for sometimes.
Add tomatoes to the skittle
Once the milk and flour settle in, add the sliced tomatoes into the pan and continue stirring the gravy.
Heat until getting desired thickness
Heat the gravy until you get desired thickness. The white mixture will become a bit reddish and you can remove it from the burner.