Oven roasted cauliflower and broccoli with mushrooms

Ingredients

• 3 cups cauliflower florets
• 2 cups broccoli florets
• 1 cups chopped mushrooms
• ½ cups chopped red onion
• 2 tablespoons olive oil
• 4 teaspoons lemon juice
• 4 teaspoons balsamic vinegar, plus extra for drizzling
• 1 teaspoon salt
• 1/2 teaspoon pepper
• 2 cloves garlic, finely chopped
• 1/3 cups chopped green onions