We do currently warm up coffee cups w/ hot water and plates in the warming drawer. It'd be nice to not have to do that though if there's a simple solution to avoid it, especially when preparing a meal and hot drinks for a number of people when time is tight and the warming drawer is already full.

It's not an insulation issue but a thermal bridge issue with the 2x6's in the wall which is why a double stud wall or exterior insulation are critical for an energy efficient home.

The 'best seller' on Amazon for a 10x21" waterproof seedling heat mat here is about $12. You could get a couple and put one or both on timers if you want. 18 watts a piece.

Though not a retrofit, a heat vent at floor level below the coffee bar area plus heated floors does the trick.

Not something with which I'd bother.

At last, a cure for my construction boots that get awful cold sitting in the garage overnight.

During winter, I stack the plates in our countertop toaster oven, let it toast for one minute or less, and then leave in there until we are ready to use them. Can't help with the cups. Hot tea and coffee takes care of ours quick enough for us.

We use our Sharp MW drawer constantly to warm plates and serving bowls. This has turned out to be one of the unexpected pleasures of our kitchen remodel.

@worthy, boot warmers are actually not unusual here. Some people use matts and others use a tube style that you put your boots upside down on.

There is always a plumbing heat tape. $30. But you can’t direct wire that. You’d need to plug and unplug it into an outlet. Or do a switched outlet. And you’d need a conductive shelving material like stainless.