One of my cats likes to lick melted butter off of my fingers ?

Yeah, cats like butter and meat. She's expecting you to get your food because you always do. This will make her fat and endanger her heath. You have to stop feeding her scraps and butter. Be strong. You're in charge here. She will learn after a while that meowing and harassing you for food wont get her anywhere if you stick to your guns. It's for her own good. You want a healthy kitty.