Not knowing how much oil you used, one could say oil. I just spritz on some. Very little in the bottom of the pan.

I use a pan about 2 inches deep for roasting veggies.....
But the roasting time and method depends on what veggies you are roasting....
I toss a mix of chunks of onion, squares of bell pepper, chunks of zuchinni and egg plant and perhaps some halved cherry tomatoes, in a bit of Kosher salt, a couple of cloves of garlic crushed, a sprinkle of extra virgin Olive oil and a sprinkle of balsamic.....toss into a pan and roast about 450....tossing about now and then, for about 45 minutes....
The oven should be hot when you put them in.
The trick is to have the heat high enough and the veggies spread out enough so that any moisture that comes from the veggies cooks away about as fast as it seeps out.
Linda C

This was just a recipe from the South Beach cookbook - I had squares of red and yellow pepper, zuchinni, summer squash, onion and I threw in some carrots. 3 T oil. Oven was preheated to 450. I had precut the vegtables and had kept in a plastic ziplock in refrigerator all day, so there was moisture in the bag. How about that? You think that contributed to that mushy mess? And that all clad roaster is probably 3" tall.

The veggies maybe started a break down before roasting.....and 30 minutes sounds like a long time at 450 to me......and another factor to the success of the dish is how spread out in the pan the veggies are....
Carrots really won't work in with the veggies you mentioned.....by the time they get done the rest are too soft.
Linda C

I use a jelly roll pan and temps of 425°- 450°. Usually roast one veggie at a time.

Sweet potato wedges = about 25 minutes
Carrot 'fries' = about 15 minutes
Asparagus = 8-10 minutes for thin, little longer for thicker
Butternut squash = about 25 minutes

huh, it's funny how everybody makes this different. I cut everything into sticks about the size of my little finger and roast at 400 for 20 minutes or till just starting to burn at the edges. I love it because you can have it on the table so quick.

I use a jelly roll pan or the bottom of my broiler pan sometimes - it's bigger than my jelly roll pan. I usually toss my vegies with about a tablespoon of olive oil and seasonings. I generally just do one type though - potatoes, asparagus, etc. I don't pay much attention to the time - just what they look like - but I don't think I've ever cooked anything much more than 15 mins - maybe 20 max.