The Butter Bell (aka French Butter Dish)
You put a little water in the base to create a bacteria-discouraging airtight seal around the butter. And you’re never again stuck with a rapidly cooling piece of toast and rock-hard butter. It’s a design that’s been around in various forms for centuries.
I’ve had a couple of these over the years. If you don’t use the butter quickly enough, it can get moldy. But if you go through a stick of butter every week or so, it’s great.