... additions to food to make an otherwise edible dish a culinary masterpiece?
Back story - on the phone to my dad lamenting that I can't get my gravy as thick and tasty as I remember it having been growing up. I always remembered the red Bisto jar on the worktop. Which yes, I use but add the juices, which is what I thought dad did...
"A dollop of Heinz".
That's the secret to the fantastic gravy... I was expecting tales of marrow or some random herb or spice... but no, tomato sauce 
Yes I've just made a cup and dipped a three slice s of bread in it for my supper. Childhood in a cup...
Anyone got any other tips? My friend has just informed me that her mum told her she used to mix a raw egg into mash...