Trim excess fat from veal or pork. Place cutlets between 2 sheets of waxed paper; flatten to one-eighth- to one-quarter-inch thickness. Combine flour and pepper in a shallow dish. Mix egg and buttermilk in another shallow dish. Coat cutlets with flour mixture, dredge in egg, then coat with bread crumbs. Let rest for 15 minutes.
Heat large skillet on medium. Add oil; when hot, carefully add cutlets. Cook 4 to 5 minutes on each side or until browned. Transfer to a platter. Garnish Wiener schnitzel with lemon wedges and serve. Serve jaeger schnitzel with German gravy.
To make German gravy: In a large saute pan, melt butter on medium-low heat until liquefied.
Slowly whisk in flour, stirring constantly until the mixture resembles dough and is dark brown.
Slowly add broth in small amounts, stirring constantly. Add salt, pepper, nutmeg, onion, tomato and mushrooms, and reduce heat to low.
Simmer, stirring occasionally, for 5 to 7 minutes, or until vegetables are soft.