For the filling: Combine the beef and lamb in a large skillet and cook over high heat until browned and well done. Drain and reserve the drippings. Place the meat in a medium mixing bowl.
Using the same skillet, caramelize the onions in the meat drippings. When the onions are nice and brown, remove them from the drippings and mix into the meat mixture.
While the onions are caramelizing, preheat a small skillet with the corn oil. Add the pine nuts and toast until golden brown (they burn quickly, so don't walk away from them). Add the pine nuts to the meat mixture along with the lemon juice, salt, cinnamon and nutmeg and combine well.
For the dough: Dissolve the yeast, salt and sugar in 1 cup of the warm water. Stir to dissolve the yeast. Add the flour to a large mixing bowl, stir in the yeast mixture and combine well. Add additional water, as needed, to make a medium-sized, stiff dough ball. Knead thoroughly. Cut into 2 equal dough balls, cover and let stand for 15 minutes.
Lightly flour a large work surface and roll out each dough ball until approximately 1/8-inch thick. Cut the dough into circles with a 5-inch round cutter. Cover and let stand a second time for 15 minutes. Try to get as many round dough pieces as you can. Any excess dough can be rolled up and saved for more meat pies.
Preheat the oven to 350 degrees F. Coat 2 sheet pans with nonstick cooking spray.
Working quickly, place 5 of the rounds at a time, on a separate work surface. Spoon a heaping tablespoon of the meat filling in the center of each round. Grabbing the opposite sides of the circle, pinch together in the middle. Then, pinch the rest of the dough closed, forming a triangular pie. Place on the prepared sheet pans. When all the pies have been formed, place the pans in the preheated oven and bake until the edges and bottoms of each pie begin to brown. Rotate the pans from bottom to top during baking. Bake until the pies are golden brown.
Recipe courtesy of Emily's Lebanese Deli in Minneapolis, MN