I almost missed this cause it was buried in another post.
This is such a great idea I wish I had thought of it
Another reptilian "do it the easy way" trick: Caramelize 6-7 pounds of onions at a time in the crockpot with a bit of olive oil (usually takes about 12 hours in mine - YMMV). Then freeze them in various sized portions. Then just grab a portion whenever a recipe calls for them - saves at least half an hour over the chopping block and stove every time.