This is an old nostalgic recipe from my grandmother..We looked forward to it every spring..I think she got it from an Amish neighbor..
This is very different, I think because of the addition of a cream sauce that can also be used on gingerbread..
Butter a 10x14 pan.(you definitely need one larger than 13x9 pan.it is too shallow and batter will run out into your oven.
In a large mixer bowl, slightly beat the egg, add 1 cup of granulated sugr and combine well.
Add the flour,b. powder, nutmeg, vanilla, salt and milk; blend. Pour the batter into the pan. Set aside.
In another large mixing bowl, mix rhubarb, (if using frozen rhubarb, do not thaw), boiling water, remaining sugars, and the food coloring.
Pour this over the batter, making sure the rhubarb is evenly distributed. (Admittedly, it looks like a rather questionable mess here, but believe me, it will come out all right).
bake for 45-50 minutes or top is golden brown and bubbly and cake is done in the center, use toothpick test.
Meanwhile prepare the cream sauce by using a small saucepan over medium-high heat, combine the sugar, flour and orange zest.Gradually add the milk, whisking till smooth. Bring the mixture to a boil, then lowe the heat to medium-low and cook for 3 minutes, whisking constantly.
Remove the pan from heat and whisk in remaining ingredients.
Remove the pudding from the oven and cool to lukewarm.
It can be reheated in the microwave.
Cut into squares and serve with the warm cream sauce.