Preheat oven to 400 degrees and butter a 9 x 13 baking dish; set aside.
To prepare the base meat mixture, add the bulgur wheat to a medium bowl and stir in the boiling hot water. Cover the bowl and let stand for 10 minutes then drain any excess water.
Add the ground lamb and sirloin to a food processor and pulse until it forms a fine paste. Remove from food processor and place in a large bowl along with softened wheat, grated onion, and All Purpose Lebanese Spice Blend. Use your hands to mix well. If mixture gets too sticky on hands, dip into a bowl of ice water.
To make the filling, heat the clarified butter in a large, deep skillet over medium-high heat. Add the meat, pine nuts, onion, and All Purpose Lebanese Spice Blend and sauté until meat is cooked through about 9-11 minutes.
To form the baked kibbeh, spread half of the base meat mixture out on the bottom of the baking dish. Next, spread the filling on top of the base layer. Finally, spread the remaining base meat mixture on top, pressing down a bit with wet hands to smooth the top.
Slice kibbeh diagonally to form small diamonds. Optional: you can drizzle on additional melted clarified butter over the top at this point.
Bake until meat is fully cooked, about 40-45 minutes. Serve with Cucumber Laban on the side.