Step 1In a food processor or food mill, puree the berries until smooth. Add the sugar, a teaspoon at a time, making sure the sauce is not too sweet.
Step 2Strain the sauce through a fine mesh strainer to remove the seeds. Cover and chill. This makes 1 1/2 cups sauce.
Step 1Heat the oven to 375 degrees. Combine the sugar, cornstarch and orange zest in a large mixing bowl. Cut the rhubarb into 1-inch pieces (you should have about 5 1/2 cups), add to the bowl and mix with your hands until the rhubarb is evenly covered.
Step 2In a food processor or mixing bowl, blend the flour, brown sugar, pepper, nutmeg, ginger and cloves. Cut the butter into thin chips, then pulse or work the mixture lightly with your fingertips until it is the texture of raw oats.
Step 3Arrange the rhubarb mixture evenly in a 9 1/2 -inch glass pie plate, making sure all the sugar doesn't fall to the bottom (if it does, spoon it over the rhubarb again). Sprinkle with the orange juice, then spoon the flour and spice mixture evenly over the dish.
Step 4Bake until bubbly and golden brown, 50 to 55 minutes, rotating the pan halfway through for even cooking. Serve warm, topped with a small scoop of ice cream and a splash of the bright red sauce.