Generously butter a 10-inch round pan or an 8-inch square pan. Preheat the oven to 350 degrees.
Wash and chop the rhubarb.
In a large bowl, combine the rhubarb with the Maine maple syrup and cornstarch.
Add the oatmeal, coconut flakes, brown sugar, butter and spices to the bowl of your food processor. Process until the mixture is crumbly.
Add the chopped rhubarb to the baking pan. Spread the topping evenly over the rhubarb mixture.
Bake until the crisp is bubbly and the juices have turned clear, about 50 minutes to 1 hour. Remove from oven and let cool.
Serve with a dollop of whipped cream, ice cream, or yogurt.