Thanks, sillage. I found the following recipe from HARD-TIME COOKERY (published in 1940) intriguing, even if my mouth felt slightly greasy after reading it.
http://bllearning.co.uk/live-extracts/114290/I love the title of this recipe. I pictured smoked, marbled bricks of the stuff.
BACON BARS, GRILLED
(to use up scraps of stale bread, cheese and bacon)
24 pieces of stale bread
12 pieces of bacon, about the same size of the bread.
½ lb.of margarine
3 oz. grated cheese
Melt the margarine. Dip the pieces of bread in it and toss them with the grated cheese. Fry the bacon. Make sandwiches of two pieces of bread, placing the bacon in between. Grill or fry on each side and serve piping hot.
Nb: Perhaps this could be a limited edition sandwich for White Castle.