Blood Sausage and Onions

Why is everything we eat so complicated.  Almost nothing but strips of salted meat can be eaten while riding a horse.  Why couldn't they take some ground meat, cook it over a fire or in a pan, place two pieces of bread around it, so it could be eaten while riding.  The length of many a journey could be shortened that way.  To make it more hearty a slice of cheese and perhaps some pickle slices or sliced onion could be added between the bread.  The smallfolk could set up small stands to sell such faire along well traveled roads and earn some coppers.