Step 1Place green onions and cheese in processor bowl. Process until cheese is coarsely chopped; set aside on foil. Do not wash bowl.
Step 2Bring water, 1/3 cup milk, butter, salt, nutmeg and pepper to taste to boil in small saucepan over medium heat. Remove pan from heat. Use wooden spoon to vigorously stir in flour until mixture is well combined and leaves side of pan, about 1 minute. Return to heat and cook, stirring often, 2 minutes.
Step 3Transfer dough to processor bowl. Turn on processor and add 4 eggs through feed tube, stopping once to scrape down sides, until mixture is thick and smooth, about 20 seconds. Add remaining milk; process 5 seconds. Add reserved cheese mixture and bacon; process 5 seconds more.
Step 4Grease 8-inch tart pan with removable ring and lightly sprinkle with water (steam will release puff from pan after it is baked). Transfer dough to tart pan. Use your finger dipped in egg-salt mixture to even dough's thickness and smooth any rough edges.
Step 5Bake at 400 degrees until well browned, about 27 to 30 minutes. Let rest 10 minutes. Remove from tart pan. Cut into wedges. Serve warm.