How to Make It
Prepare the Crust: Preheat oven to 325°F. Wrap outside of a lightly greased 9-inch springform pan with heavy-duty aluminum foil. Stir together cookies, butter, and sugar. Press onto bottom and 1 inch up sides of pan. Bake until set, 7 to 8 minutes. Transfer to a wire rack; cool completely, 30 minutes.
Prepare the Cheesecake: Beat cream cheese with a heavy-duty stand mixer on medium speed until creamy, 3 minutes. Gradually add sugar and flour, beating until smooth. Add eggs, 1 at a time, beating after each addition. Add egg yolks, 1 at a time, beating after each addition. Beat in zest, juice, and vanilla on low speed just until combined. Pour into prepared pan (it will be full); place on a rimmed baking sheet.
Bake at 325°F until center is almost set but still wobbly, 1 hour and 10 minutes to 1 hour and 20 minutes. Transfer to rack; cool completely, 2 hours. Cover with aluminum foil; chill 8 to 12 hours. Run a knife around outer edge; remove sides of pan.
Prepare the Topping: Stir together marmalade and juice in a microwavable bowl. Microwave on HIGH, about 45 seconds; stir to make a glaze. Arrange grapefruit slices on Cheesecake; brush with glaze.