Preheat oven to 400°F
Slice off the top of the head of garlic
Place the leeks, cauliflower, broccoli, zucchini, potatoes and garlic on a large sheet pan
Drizzle with olive oil, 1 tsp salt and pepper
Roast for 30 minutes, until all vegetables are fork tender
About 10 minutes before the vegetables are done, add the broth and peas to a small pot and heat until simmering
Add everything (only add half of the garlic cloves) to a blender, including remaining ½-1 tsp salt and blend until smooth
Serve with pesto grilled cheese croutons (optional)