Combine the flours and salt in a food processor and process for 10 seconds
Add lard in 20 blobs and cut in the butter in 20 chips; pulse just until the largest pieces of fat are pea size, about 12 times
In a bowl, blend the egg, ice water, and vinegar and pour over the flour mixture; pulse until the mixture masses to the point of being crumbles, 8-10 times
Turn the crumbles on to the counter and pat into a ball (should still have some blobs of cold fat)
Slice the ball in half and pat each half into 5" rounds; wrap in foil and chill for at least 30 minutes, (2 hours is better) before rolling out 1/8" thick.
If patching is necessary, press dough together without water.