Heat oven to 400. Toss leeks, zucchini, eggplant and turnip in olive oil. Season with rosemary, red pepper flakes, lemon zest, plenty of salt and pepper. Taste. Keep adjusting the seasoning until the vegetables become as addictive as candy; they're the main component of this dish so you really want them to be irresistible. Slice 1/2 of the lemon into 1/4-inch half moons and arrange over the vegetables. Roast about 30 minutes, or until the vegetables turn slightly creamy with crisp, golden brown edges. Remove from oven, squeeze the other half of the lemon over the vegetables and toss. Adjust seasoning as needed.
Drizzle pasta with olive oil and toss with garlic powder. Toss with roasted vegetables (or serve them on the side). Season with more black pepper, then sprinkle parsley over everything. You know I can't resist a sundried tomato, so I add a couple in at this point. Feel free to leave them out (I'll eat yours).
I like to add a ton of nutritional yeast on top for an extra cheesy kick, Mom prefers fresh parmesan cheese. Neither option is necessary, both options are delicious.
Note: *You can use regular eggplant if you can't find grafitti (it's light purple with white stripes), but grafitti has thinner skin and cooks more quickly. Peel the eggplant or increase roasting time if using regular eggplant.