Rhubabrb Upside Down Cake - Nan (Alias Ms. Magoo)

I think (it's been many years since I made any) we cut up the rhubarb, put in cake pan, sprinkle with jello (strawberry) and some flour mixed for thickener (could use xanthamgum), and butter dotted on top, covered with crumble topping (could use almond flour, butter combo), and baked. As the filling cooked, the juices would bubble up thru the topping and would cause it to get the flavor and a great texture too. MMMMMM, after it cooled somewhat, top with whip cream and enjoy!