Prepare polenta: Bring milk and heavy cream to a boil in a sauce pot. Stir in polenta; reduce heat to a simmer and continue cooking and stirring for 3-5 minutes or until polenta thickens.
Remove from heat and stir in cheeses, thyme and salt.
Heat oven to 400° F. Cook bacon until brown and slightly crisp. Remove to cool.
For each serving, spray-coat 12 (8 oz.) ramekins with cooking spray. Line the inside of each ramekin with 2 slices bacon (to act as a crust). Place a 6 oz. scoop of polenta in the center of the ramekin, pressing down to fill the bottom and hold the bacon in place. Crack an egg on top of the polenta; break the yolk. Sprinkle 2 tablespoons shredded cheddar over egg.
Bake at 400° F for 12-15 minutes until puffed, browned and egg is thoroughly cooked and firm. Run paring knife around the inside edge of the ramekin; invert to remove. Serve over 2 cups dressed mixed greens.