HEAT oven to 350ºF.
BRING water, piloncillo, cinnamon stick and cloves to boil in medium saucepan; simmer on medium heat 20 min. or until reduced to 1 cup, stirring occasionally. Meanwhile, place bread slices, in single layer, on baking sheet. Bake 10 to 15 min. or until toasted on both sides, turning occasionally. Brush both sides of toast slices with butter. Bake 10 min.
TRANSFER bread slices to 13x9-inch baking dish. Discard cinnamon stick and cloves from hot syrup. Drizzle 2/3 cup syrup over bread; top with raisins, nuts and cheeses.
BAKE 12 to 15 min. or until cheeses are melted and golden brown. Drizzle with remaining syrup.