Sift and mix 2 c flour, baking powder and salt. Cut in shortening until "mealy", add enough milk to make a soft, puffy dough eash to roll out. Round up on lightly floured surface. Knead lightly 20-25 times. Roll out to about 1/4 inch thick. Make sure it is big enought to cover the bottom and sides of a 9X9-inch pan andhave enough for a top. Place dough on the bottom and up the sides.
In another bowl, combine the eggs, 3 Tbsp milk, sugar and mix well. Stir in the 1/4 c flour and nutmeg. Add the rhubarb and when mixed, pour into the dough lined pan. Dot with the butter.
Dampen the top edge of the dough with water. Place the top layer of dough over the pan and pinch the edges together all around the pan. Cut off any excess around the edges of the pan. Sprinkle with a cinnamon-sugar mixture and put in the oven at 400 degrees for 50 to 60 minutes. Check the last 10 to 15 minutes and cover with foil if browning too fast. After taking it out of the oven, let it stand for 20 minutes to cool and thicken. Enjoy with ice cream or half and half.