Place rhubarb and sugar in a saucepan and simmer over medium heat, stirring frequently, until rhubarb is very soft and saucy. It’s OK if there are still chunks of rhubarb in it. Chill it thoroughly in the refrigerator or freezer.

Cut cake into about 10 (1/4-inch-thick) slices. From the remaining cake, cut about 3/4 cup small cubes.

Place ice cream into a large bowl and let rest at room temperature for about 10 minutes to soften. Measure 2 cups rhubarb puree into the bowl and gently fold into the ice cream. It should be pretty evenly distributed, but it’s OK if it still looks a little marbled.

Line the bottom of a loaf pan or small cake pan with half the angel food cake slices. (You may place a strip of parchment in the bottom of the pan to help remove the cake later — see the video.) Spoon half the rhubarb ice cream into the pan. Scatter the cake cubes over the surface and top with the remaining ice cream. Place remaining cake slices on top and wrap in plastic wrap. Freeze cake for at least 6 hours; overnight is best.

To serve: Cut around the outside of the cake with a sharp knife and wiggle/invert cake out onto a chilled serving platter. If needed, you can dip the pan in hot water for a few seconds. Decorate the top of the cake with whipped cream and fresh strawberries.

Cut into individual slices and serve with additional rhubarb sauce and fresh strawberries.