Heat oven to 350. Grease and flour an 8" springform pan.
Peel, core, and cut pineapple into 1/2" pieces. You need 2 cups.
In a blender or food processor, puree a third of the pineapple to make 1/2 cup puree, then add water to measure 2/3 cup. The remaining pineapple pieces will be used when assembling the cake.
In a small bowl, stir together flour, baking soda, and salt. Using an electric mixer on high speed, beat eggs for 4 minutes. Gradually add granulated sugar, beating 4 minutes on medium speed (or until sugar almost dissolves). Gradually add flour mixture, beating on low speed until combined.
Heat pineapple puree and butter until butter melts; Add to batter. Pour batter into prepared pan.
Bake 30 minutes or until toothpick comes out clean.
Cool 10 minutes on wire rack. Remove from pan, cool completely on wire rack.
Prepare topping/filling when cake is cool. Cut cake horizontally into two layers.
Beat whipping cream with powdered sugar until soft peaks form.
Place one layer on a serving platter. Spread with half of the whipped cream. Cover with half of the pineapple pieces. Top with second cake layer. Repeat whipped cream and pineapple pieces.
Heat marmalade with 1 tablespoon water. Cool slightly, then drizzle over cake.