>Butters both sides of both slices of bread.
I reckon if I took my RepRap 3D printer apart, I could probably achieve a good bit of that with the components. Extrude (one stepper motor) butter on the toast in an X-Y grid pattern ( another 2 stepper motors), leaving me one stepper motor left over. The bed of the 3D printer is heated....
Hmmm.... I'll go away and have a think about this.
Or..... Ryobi make a mastic gun that takes a 18v battery*.... could be re-purposed to apply cold butter to bread, methinks. It wouldn't be automatic, but it would be fun.
* Not completely stupid.... applying a long thin bead of a stiff mastic like polyurethane can be tiring.... if it was a job I did a lot I might consider one.