So. One can't roast all the vegetables for the same amount of time, or some are undercooked and some are burnt. So, here is my rough and ready rule: roast them as you chop. The expanded version is to then chop them in the longest-to-cook to shortest-to-cook order. In general, each batch of veggies spends at least 10 mins in the oven before the next batch is added.
So. Start with your emply pan in a 400 F oven.
Scrub your veggies and dry them.
Chop any of: potatoes, beets, parsnips, carrots, pearl onions, and hardskinned squash like acorn or butternut. I peel my squashes because I can't digest their skins, but other people leave them on - let your tummy be your guide. I don't peel anything else (okay: I peel the onions, fiddly things that they are). (I may break this veggie group into two, just for ease of oil coating.)
Chuck them in a bowl with a dollop of olive oil plus your preferred herbs (see below), and stir until thoroughly coated.
Throw them into the hot pan, and put the pan back in the oven.
Chop any of: sweet peppers, cherry tomatoes, cauliflower. Roll in herby oil & fling in pan & return pan to oven.
Chop brussel sprouts. Oil, pan, oven.
Chop mushrooms. Oil, pan, oven.
After the last addition, keep in oven for an additional 20 to 30 mins (or longer, as needed).
Serve with a creamy cheese like cream cheese or goat cheese. And bread for sopping up the juices.
I use different herbs in each oil bath, depending on the veggie.
Potato + rosemary
Tomato + basil
Onions + parsley
Beets + marjoram or dill
Carrots + savoury
Parsnips + savoury
Butternut or acorn squash + ginger or cumin
Cauliflower + cumin or paprika & turmeric or paprika & chili powder
Sweet pepper + oregano
Brussel sprouts + nutmeg
Mushrooms + thyme
Oh yes: I salt & pepper every oil bath.
I confess that I haven't used potatoes yet because even only one each (except onions, brussel sprouts, & mushrooms) fills your pan pretty quickly. I make a big pan on Sunday & we use it for lunches throughout the week.