Cookbook author Sarah Lee Chase calls this a serendipitous scramble of corn bread, rhubarb & walnuts or an absolute must with roast spring chicken. In any case, it was a hit at our annual Easter gala!
Preheat oven to 325 degrees. Butter a 10" or 12" gratin dish or shallow casserole.
In a large mixing bowl, toss together the rhubarb and sugar. (I used 2 packs of Dole frozen rhubarb, thawed and patted dry).
Melt 2 T. butter in a medium skillet over medium high heat. Add the onion and saute until quite soft, 10-15 minutes. Remove the onion from the skillet and combine with the rhubarb. Melt the remaining 6 T. of butter in the skillet and add it to the rhubarb mixture along with the corn bread crumbs and walnuts. Stir well to combine.
Spread the nixture in the prepared dish. Drizzle the cassis evenly over the top. (If you don't have cassis, use any berry flavored liqueur or maybe even apple juice?).
Bake until the rhubarb juices are bubbling and crumbs are lightly browned, 40-45 minutes. Serve at once.