For the crust:

Cup of Yum
1. Measure out 1/4 cup water into a glass measuring cup and stick it in the freezer.
2. In a large bowl, whisk together flour, sugar, and salt.
3. Use a pastry cutter or fork to cut in the shortening. Cut until it looks like coarse crumbs. Don't overdo it!
4. In a small bowl beat one egg. Pour out half (into the sink or into another container, or heck, into a frying pan). You can just eyeball it.
5. Add the half beaten egg to the cold water that you put in the freezer. Beat it together, then add it to the shortening mixture. Stir until it is just coming together, then use your hands to knead it once or twice (only to make it come together). Divide the dough in half.
6. Generously sprinkle flour onto a sheet of parchment paper. Roll the dough with a rolling pin, using as much flour as you need so that it doesn't stick. Invert the parchment paper onto a 9-inch pie pan and gently peel off the paper. Arrange the pie crust and trim edges as necessary.
7. Repeat with the remaining dough, up until the invert step.

For the pie:

1. Preheat the oven to 400 F.
2. In a stand mixer or large bowl, beat eggs on medium speed for about 2 or 3 minutes, until they are a light lemon color.
3. Add the sugar and beat on medium for one more minute.
4. Add 2 tablespoons of instant tapioca and combine thoroughly.
5. Add the salt, flour, and nutmeg, and beat well.
6. Stir in the rhubarb with a rubber spatula.
7. Pour into the prepared pie crust. Mound the rhubarb slightly in the middle. Sprinkle the cut butter evenly over the mixture.
8. Transfer (invert) the top crust over the pie and seal the edges.
9. Cover the edges of the crust with a pie crust cover or foil (see note).
10. Bake in the preheated oven for 40 to 45 minutes, until the crust is golden.
11. Remove from the oven and let stand until room temperature, several hours. You can speed things up by putting it in the fridge if you want.
12. Store covered on the counter. Warning: this means you will take bites of it every time you pass through your kitchen. Sorry in advance.