Video from CHOW here on sweating vs. caramelizing (wouldn't let me embed).
The secret? Cook longer for caramelizing. Medium heat for both, add salt from beginning - but (and this is key and what I wasn't sure about): you don't need to add any sugar to caramelize. The longer cooking brings out the natural sugars.
I just ate some roasted beets & sweet potatoes, and some of the bits were caramelized and HOLY MOLEY THAT'S GOOD! But the recipe I have calls for a bit of brown sugar - and I think I'll omit next time if it's unnecessary.
Dark Chocolate Peanut Butter Brownies
55 minutes ago