Many years ago I worked at a restaurant and they just used to mix Worcestershire Sauce, Tomato Sauce, and Vanilla Ice-cream. No set amounts just enough to do the number of people at the time, and taste it and add a bit more of whatever it needs, eg.. more colour, add a bit more tomato sauce, or more kick, add more Worcestershire etc.....Stir it in a little dish until it tastes just as you want. You always have those ingredients around, and it's quick and easy. I am Australian and the ketchup we get here is a bit strong and most people use tomato sauce on pies etc.