Pressure cooking for one?
You should never use less liquid than is recommended by the manufacturer.

If you use less you run the risk of boiling your food dry or burning it since the level of heat to maintain the pressure may increase.

Get used to leftovers.  You can cook several portions reserve the excess for later use.  This will save you time and money.  I usually will cook a whole chicken and shred the meat and use it for several meals until it's gone.