For the crust

1. Mix. In a food processor, blend together flour, butter, shortening, and salt just until mixture resembles coarse crumbs with some roughly pea-size butter lumps.
2. Add water. Drizzle 3 tablespoons ice water evenly over the mixture and pulse in processor until incorporated. Squeeze a small handful together. If it doesn’t hold together, add more ice water, 1/2 tablespoon at a time, pulsing until just incorporated, then test again.
3. Gather together. Gather dough together into a ball, then flatten into a 1/2-inch thick disk. Wrap dough in plastic and chill, until firm, about 1 hour.
4. Roll out. Roll out dough into a 12-inch round on a generously floured surface with a floured rolling pin and fit into a 9-inch deep dish pie plate. Trim excess dough, if necessary, leaving a 1/2-inch overhang, then fold overhang under pastry and press against rim of pie plate to reinforce edge. Decoratively crimp edge (if desired) and lightly prick bottom and sides of shell with a fork.
5. Chill. Chill the dough in the pie pan until firm, about 30 minutes.
6. Prep oven. Heat oven to 375 degrees F.
7. Blind bake. Line shell with parchment paper and fill with dried beans (or pie weights). Bake until pastry is pale golden along rim and set underneath parchment paper, about 20 minutes. Carefully remove paper and beans and bake shell until bottom and sides are pale golden, about 10 minutes more. Cool completely in pie plate on a rack, about 20 minutes.

For the filling

1. Mix. Whisk together eggs, cream, herbs, seafood seasoning, salt, pepper, and nutmeg, then stir in cheeses and crabmeat.
2. Bake. Pour filling into pre-baked crust and bake until filling puffs and is no longer wobbly in center when quiche is gently shaken, 40 to 50 minutes.
3. Serve. Cool quiche in pie plate on a rack 15 minutes before cutting.