Preheat oven to 350°. Bring first 2 ingredients to a boil over medium-high heat. Reduce heat to low, and simmer 30 minutes or until reduced by half. Stir in 1 cup cheese.
Stir together cornstarch and 1 Tbsp. water. Whisk into cream mixture until thickened.
Cook collards in boiling salted water to cover 5 to 7 minutes or until tender; drain and pat dry with paper towels. Cool 10 minutes; coarsely chop.
Cook bacon in a large skillet over medium-high heat, stirring often, 8 to 10 minutes or until crisp. Add onion, and cook 5 minutes or until tender. Stir in collard greens, and cook, stirring constantly, 3 minutes. Stir in cream mixture. Add salt and pepper to taste.
Pour mixture into a lightly greased 11- x 7-inch baking dish. Stir together panko, olive oil, and remaining 1 cup cheese; sprinkle over collard mixture.
Bake at 350° for 35 to 40 minutes or until breadcrumbs are golden brown. Let stand 5 minutes before serving.