Combine sugar, basil, salt, mustard, flour, and corn flour in a bowl. Add shortening and blend (by hand or low-speed dough hooks) until ingredients just come together and resemble very coarse meal. Gradually add the cold water and continue mixing just until the water is absorbed. Be careful not to overmix, or dough will be too tough!
Gather dough into a ball and refrigerate at least 4 hours, or overnight.
Divide dough in half and form each half into a ball. Liberally flour
the working surface and rolling pin. Place a dough ball on the floured
surface and roll it out, keeping it even and round. Dust with flour as
necessary until circle is 11 inches in diameter. Fit circle into 9 inch pie
tin and crimp edges. Repeat with remaining ball of dough. Set aside to
prepare Crawfish Pie filling.
Makes 2 9 inch pies.
Source: Fiery Foods I Love by Paul Prudhomme