What is it?

Shoofly pie (or shoo-fly pie) is a fluffy molasses pie considered traditional among the Pennsylvania Dutch and also known in Southern cooking.

The term "shoo-fly pie" first appeared in print in 1926.^[1] The pie may get its name because the molasses attracts flies that must be "shooed" away ^[2].

http://en.wikipedia.org/wiki/Shoofly_pie

Recipie I had gotten of a NPR show called The Splendid Table (great cooking radio show btw):

Shoofly Pie

From New Recipes from Quilt Country: More Food & Folkways from the Amish & Mennonites, by Marcia Adams

Makes one 9-inch pie; serves 8

This is the best shoofly pie I’ve eaten, and believe me, I’ve tried many. Some versions are dry and soft; others are quite gooey and moist. This one falls somewhere in between, and is thick and unabashedly pleasing. Shoofly is authentic American pie that comes to us from the Pennsylvania Amish and Mennonites and the Pennsylvania Dutch; we should be grateful to them forever.

Surprisingly, shoofly pie is not as popular in other Amish and Mennonite communities. It is found in Ohio; but in Indiana, if you ask for a piece of shoofly pie in a restaurant, the Amish girl who serves it will rather disparagingly tell you it’s made only for the tourists – a thousand pities.

• Pastry for a 1-crust 9-inch pie (page 270)
• 1 cup all-purpose flour
• Two-thirds cup light brown sugar, packed
• 1 rounded tablespoon cold butter
• One-fourth teaspoon salt
• 1 egg
• 1 cup light molasses
• Three-fourths cup cold water
• One-fourth cup hot water
• 1 teaspoon baking soda

Preheat the oven to 350 degrees. Roll out the pie pastry and line a 9-inch pie pan; set aside.

In a food processor bowl, combine the flour, brown sugar, butter, and salt. Remove one-half cup of the mixture and set aside. Transfer the rest to a medium mixing bowl. In a small bowl, beat the egg lightly. Add the molasses and cold water, and blend but do not beat; you don’t want bubbles in the batter. Set aside.

In a small bowl, mix the hot water with the baking soda and blend into the molasses mixture. Add to the flour mixture and mix well. Pour into the pie shell and top with the reserved crumbs. Bake for 35 minutes. The pie will appear quivery but will firm up as it cools. Transfer to a rack to cool completely before cutting.

http://splendidtable.publicradio.org/recipes/dessert_shoofly.html