1Preheat oven to 350°. Insert paper liners into 20 muffin cups; set aside.
2Beat cake mix, 1 cup orange juice, and next 5 ingredients at low speed with an electric mixer until combined. Scrape sides of bowl with spatula, and beat at medium speed 2 minutes or until batter is thick and well combined. Spoon about 1/3 cup batter into each liner.
3Bake at 350° for 18 to 22 minutes or until a wooden pick inserted in center comes out clean.
4Brush tops of warm cupcakes evenly with remaining 2 tablespoons orange juice. Let cool in pans on wire racks 5 minutes. Remove from pans, and let cool completely on wire racks.
Beat first 3 ingredients at low speed with an electric mixer until creamy. Gradually add sugar, beating until combined. Gradually add orange juice, beating at medium speed 30 seconds or until frosting is spreadable. Beat at medium-high 30 seconds or until fluffy.
Spread about 1 heaping tablespoon of Marmalade Buttercream Frosting on each cupcake.