In a saute pan, make the blonde roux first. Melt butter on low-medium heat, then add flour and wisk continuosly for about 10 minutes until it starts to turn light blonde color and smells a little 'nutty'. Time may vary; it's more about the color and smell.
Add roux in a cold stock pot to stop the cooking, and add cold chicken stock and corn. Bring to a boil, stirring occasionally. Reduce to simmer, add fresh garlic and garlic flakes, thyme, and rosemary (if desired). Simmer for 10-12 minutes.