Poblano Chile Soup (Sopa de Chile Poblano)

Ingredients

• 2 lb. poblano chiles
• 6 tbsp. unsalted butter
• 1 large white onion, roughly chopped
• 1 rib celery, roughly chopped
• 1 medium carrot, roughly chopped
• 4 oz. spinach, roughly chopped
• 1⁄3 cup minced parsley
• 4 cups chicken stock
• 2 cups milk
• 1 cup heavy cream
• Kosher salt and freshly ground black pepper, to taste
• 1⁄2 cup crema or sour cream
• 1 serrano chile, stemmed, seeded, and minced
• Fried tortilla strips, to garnish