In large pan, heat olive oil or water over medium high heat.
Saute onions for 5 minutes with a pinch of salt adding more water, 2 tablespoons at a time, if necessary.
Add garlic to the pan and saute for 30 seconds.
Add carrots and mushrooms , salt and more water if necessary.
Cook for 7-10 minutes until liquid from mushrooms has been released and mostly cooked off.
Stir in the corn and spinach and saute for a minute or so until the spinach has just wilted.