Caramelising onions takes a lot of time to get that sweet flavour and deep colour. Typical shortcuts still take valuable space on your stove. Alton Brown shares his secret for doing it in the microwave.
If you just pop a plate of onions in the microwave, they're not going to brown. He adds some brown sugar along with some butter for colour and flavour. He also adds some bicarb soda, which speeds up the browning process on the stove as well.
How to Make Caramelized Onions in the Microwave [Alton Brown]