Three ingredients to make a delicious olive oil perfect for vinaigrette, dipping, sauteing, or...Extra virgin olive oil (though plain old slutty olive oil would work too,) yellow onions (Vidalia-type sweet onions are too mild,) and Jane's Krazy Salt (sea salt would be just fine) are all you need.
Slice the onions, put them in a shallow pan with about a half an inch of olive oil, flip the slices to make sure they're well-coated, sprinkle with salt. Put in a 350 degree F oven for about an hour till they are beginning to brown and smell wonderful.
Two big cooking trays and four onions yielded about a quart and a half of oil. The oil is a little cloudy -- that's the flavor -- and it keeps unrefrigerated for several weeks. Of course you can refrigerate it but we tend to use it up fairly quickly.This was a serendipitous discovery when I was roasting onions for some recipe or other and decided to try the residual oil on a salad.