Cook pasta as directed on package, omitting salt. Drain pasta, reserving 1/3 cup cooking water.
Heat 1 Tbsp. oil in large saucepan on medium heat. Add onions and thyme; cook and stir 5 min. Add reserved cooking water, Cooking Creme and cheeses; cook and stir 2 to 3 min. or until cheeses are melted. Add pasta; mix lightly. Transfer to 9-inch square baking dish sprayed with cooking spray.
Drizzle remaining oil over bread cubes; toss to coat. Sprinkle over pasta mixture.
Bake 12 min. or until pasta mixture is heated through and bread topping is golden brown.