Sometimes you'll get toolbox parts from the reward chests (the ones you need to wait 10 minutes to open)

The kitchen cabinet

Tapping the toolbox (Level 4+ I think) will sometimes net you the first level of the toaster (it looks like a blue board with two metal bars on top of it), and once you merge that up to Level 6 it'll get you a toaster, which will spawn bread slices in any free space next to it. Merge those to make sandwiches. Hope this helps!