Butter wouldn't melt. No, really.
SpreadThat kitchen knife Price: €20 Rating: **
At least once a week in my house, someone leaves the butter in the fridge. The result is a block that is impossible to spread on toast without ripping the bread apart. This would-be clever gadget is supposed to use your hand's natural body heat to warm up the blade, letting it cut through freezing butter a little quicker.
To do this, it uses a special copper alloy that is a conductor for heat from the hottest part to the coldest. The only problem is that it takes a while for the knife to warm up - about a minute, in fact.
In other words, it doesn't make all that much difference, unless you're prepared to stand around with the device for a while beforehand.