It is sage-forward breakfast sausage fat, usually medium-spicy from red pepper in the sausage as well as other common seasonings. Bits of the sausage remain, but basically flour is added to the fat left after cooking sausage and made into a roux which is used to thicken milk added as the liquid, with salt and a large amount of ground black pepper which ends up being the primary seasoning which comes through. It is delicious.

It does not translate well to the UK palate simply because of the terminology used, and the difference in sausages (being ground sausage in patty form here, typically). It is a hearty, very savory and fat, salt, and carb-forward breakfast of the sort you would expect a farm worker to want.