Dissolve yeast in warm water in a small bowl; let stand 5 minutes. Add milk and oil, stirring with a whisk. Lightly spoon flour into dry measuring cups; level with a knife. Combine 2 cups flour and sugar in a small bowl. Add flour mixture to yeast mixture, stirring with a whisk until just combined. Cover and let stand in a warm place (85°), free from drafts, 1 hour or until mixture is bubbly. Stir batter. Cover and refrigerate 24 hours.
Let batter stand at room temperature 20 minutes (batter will be thick and spongy). Coat a waffle iron with cooking spray, and preheat. Stir batter; add 1/2 cup flour, salt, and egg, stirring with a whisk. Add cheese and ham; stir well. Spoon about 1/2 cup of batter onto hot waffle iron, spreading batter to edges. Cook 3 to 5 minutes or until done; repeat procedure with remaining batter.
To prepare sauce, combine syrup and mustard in a bowl; stir with a whisk. Serve with waffles.