Avocado Vichyssoise

• 6 green onions
• 4 tomatillos husks removed
• 3 poblano chiles
• 2 ripe avocados seeded (peeled)
• 1 serrano chile seeded
• 1 chipotle chile pureed
• 1/2 bunch cilantro stems removed
• 1,400 ml milk up
• 290 gr potatoes (peeled)
• 120 ml sour cream