1. Preheat oven to 425°. Combine first 4 ingredients in a large bowl. Stir in broccoli and cauliflower, tossing to coat. Season to taste with salt and pepper; transfer mixture to a large rimmed baking sheet.
2. Bake, stirring occasionally, 15 minutes or until vegetables are very tender and cauliflower is lightly browned. Squeeze lemon wedges over vegetables, tossing to coat.