In Italy, antipasti are meant to whet your appetite. (Granted, when I ate out in Italy, my appetite needed little whetting -- what with all the whiffs of freshly-made pasta and roasted tomato sauce drifting from the kitchen to my table.) Nonetheless, in Italy, antipasti are simply appetizers, mere preludes to the main dish. In my house, they're just part of the meal. After all, roasted vegetables with a splash of quality balsamic vinegar and just the right amount of good olive oil make a perfect accompaniment to whatever's being served. In my humble opinion, they need not precede the main course -- in fact, they do just fine right alongside it.
By far the best thing about antipasti is their simplicity. Season, drizzle, and roast, that's all there is to it! These simple steps work wonders for eggplant, zucchini, onions, tomatoes, even sweet potatoes. The trick is to slice thinly, and flip once half-way through the roasting process so that both sides crisp up. If you're sparing with the oil, as I am, best use a pastry brush, which will spread the oil over the entire surface without soaking them all too much. And while cooking spray is fine for the pan, I strongly recommend sticking to real olive oil for the vegetables themselves; olive oil is a strong player in the saturated, concentrated flavor that antipasti develop.
I can safely say that this "recipe" has no recipe, but a method, instead: slice whatever vegetables you use about 1/4-1/8 inch thick, as uniformly as possible. Line a roasting pan with a single layer of vegetables. Brush each side with olive oil, sprinkle salt and pepper, and add herbs if you like (I favor sage, pictured below, for eggplant, and rosemary with sweet potatoes, onion, and a new addition -- turnips).
Bake at around 400 degrees for 15-20 minutes until the tops are browned; flip, and bake another 10-15 minutes. Check regularly to avoid burning (which I unfortunately have a tendency to do!). Once the vegetables are out of the oven, transfer to a platter, drizzle with good balsamic vinegar, add salt and pepper to taste, and bring to room temperature before serving.