Position rack in center of oven and preheat to 350°F. Butter two 2-quart soufflé dishes or baking dishes.
Heat first 4 ingredients in heavy large saucepan over medium heat until bubbles form around edge of pan. Gradually stir in cornmeal. Add escarole. Stir until mixture is very thick and creamy, about 5 minutes. Remove from heat. Add cheese and butter and mix until butter melts. Season with generous amount of pepper. Beat egg yolks to blend and gradually stir into cornmeal mixture. Beat whites in large bowl until stiff but not dry. Mix 1/4 of whites into cornmeal mixture. Gradually fold in remaining whites.
Divide mixture between prepared dishes. Bake until puffed, golden and knife inserted into centers comes out clean, about 55 minutes. Serve hot.
