Brush 4 gratin dishes with olive oil, arrange potatoes in the dishes, brush them with olive oil and season. Then prebake 5 to 6 minutes at 400 degrees. Prepare filling by sauteeing the vegetables and aromatics in olive oil until lightly caramelized. Stir in the ras el hanout and cook until strongly aromatic. Add wine and raisins and reduce until moist but not liquidy. Lightly wilt in spinach, adjust seasoning and fill in shells.
Prepare crust by steeping bulghur with hot water then flavoring with citrus, walnuts toasted with garlic and olive oil. Season and mound over filling.
Bake all 12 minutes at 375 degrees