PLACE 6 of the bread slices in bottom of greased 13x9-inch baking dish. Top with layers of half each of the ham, broccoli, onion and Singles. Repeat layers, omitting Singles; store remaining 4 Singles in refrigerator until ready to use.
BEAT eggs and seasonings in medium bowl with wire whisk until well blended. Gradually add milk, beating well after each addition. Pour over ingredients in baking dish; cover. Refrigerate at least 3 hours or overnight.
PREHEAT oven to 350°F. Bake, uncovered, 45 min. Top with remaining 4 Singles; bake an additional 10 to 15 min. or until center is set and Singles are melted. Let stand 10 min. before cutting to serve.