Chilled Corn Soup with Crispy Corn and Panko Topper
For soup: In a 4- to 5-qt. pot melt butter over medium heat. Add onion and garlic. Cook and stir 3 to 4 minutes or until softened. Add 4 cups corn kernels; cook 1 minute. Add reserved cobs and the chicken broth. Bring to boiling; reduce heat. Simmer, covered, 25 minutes.
Remove from heat. Cool 20 minutes. Discard cobs. Using an immersion blender, blend until smooth. Strain through a fine- mesh sieve into a bowl, pressing solids. Discard solids. Stir in salt. Chill, covered, at least 4 hours. Whisk yogurt into soup until smooth.
For topper: In a large skillet heat olive oil over medium heat. Add remaining 1 cup corn and the panko; cook 2 to 3 minutes or until browned. Top soup with corn-panko mixture, feta, dill, and zest.