Chilled Tomatillo and Yogurt Soup - SippitySup

Ingredients

• 1 pound tomatillos, hulled and washed
• 3 garlic cloves, unpeeled
• 1 serano chile
• 1 cup peeled, seeded, and roughly chopped cucumber
• ¼ cup roughly chopped onion
• ¼ cup roughly chopped cilantro, plus more for garnish
• ½ cup homemade or low-sodium canned chicken stock, skimmed of fat
• 1 tablespoon freshly squeezed lime juice
• ½ teaspoon coarse salt
• ½ cup plain nonfat yogurt
• ½ cup water
• 2 avocado, cut into cubes (optional)