Complex sentence: However, unlike the French, it is made with oil or bacon fat and more lately olive oil, and not butter, and it is used as a thickening agent, especially in gumbo and étouffée.
Split into simpler sentences: However, unlike the French, it is made with oil or bacon fat and more lately olive oil, however, not normally with butter. It is used as a thickening agent, especially in gumbo and étouffée.