Crumble saffron into warm stock to steep a little while.
Heat 2 tbsp vegetable oil in medium-size skillet over high heat until almost smoking. Carefully add pumpkin seeds and cook around 30 seconds until puffed with a nutty fragrance. Be extra careful not to overcook or they will become bitter and will ruin the dish. Quickly scoop onto paper towels to drain.
Add olive oil to same skillet over medium heat until very hot. Add chopped onions and garlic and cook until just wilted, about 3-5 minutes. Add bread slices and cook until golden brown on both sides. Add peppercorns, cloves, cinnamon, and oregano. Cook about 2 minutes more until aroma is released. Pour in capers with their brine. Stir well and simmer , uncovered, for 5 minutes over low heat. Add chicken stock and simmer another 5 minutes. Remove from heat and let it cool slightly. Pour it into a blender or food processor and process for 30 seconds. Add pumpkin seeds and process another 30 seconds until smooth.
Preheat oven to 350°F. Season chicken pieces with salt and pepper. In a wide heavy skillet, heat remaining 3 tbsp vegetable oil over high heat until rippling. Brown chicken a few pieces at a time, around 3 minutes on each side. Remove to paper towels when browned and continue to brown more pieces until done.
Place the chicken in a lidded casserole large enough to hold the pieces. Pour sauce over, cover, and bake for 40 minutes. Serve from the casserole with some white rice, beans, and a green vegetable.