Look into a 12 volt crockpot. Larger truck stops have them. They are about 1qt, maybe a little larger, but work really for two or three people. I have used mine for 7-8 years now, still works great.
I did a test when I got it, filled it with water and hooked it to a fully charged battery. After 2 1/2 days the battery came down to 11.7 volts.
I use mine in my van or in the TT. In the van you start smelling supper after about two hours. Hard to keep driving. In the TT I plug it into the 12v outlet by the sink, put the crockpot in the sink and away we go.
It usually takes about 6 hours before meal is done, depends on what you want. Meat such as chicken or pork take about the 6 hours.
12 volt works great and gives you another option for cooking.