How to Make It
Preheat the oven to 400°F. Coat the cut side of the garlic halves with cooking spray and wrap tightly in foil.
Line 2 large, rimmed baking sheets with parchment paper. Arrange the foil-wrapped garlic, beets, and onion, separately, on 1 baking sheet. Arrange the squash, cauliflower, and haricot verts, separately, on the other. Drizzle the vegetables with the oil and toss individually to coat. Roast at 400°F until tender and golden, 40 to 45 minutes for the garlic, beets, and onion; 15 to 20 minutes for the squash, cauliflower, and haricots verts.
Cool completely, about 20 minutes. Store individually in ziplock plastic bags. Refrigerate until needed.