Bisco is the main base for a lot of mcdonalds breakfast products. in Britain it is called a scone, not to be confused with the delicious sweet treat. Theyre made of wheat, or oatmeal with baking powder as a leavening agent and baked on sheet pans. A scone is often slightly sweetened and occasionally glazed with egg wash. they feature as the bread of choice (encasing the tasty fillings) of all the Biscuit products. these are not available in Britain as theyre only eaten with sweet fillings in Britain and it would be weird.