Pre-heat oven to 375°F.
Cut off the top quarter of each bell pepper (the stem end) and reserve as a lid. Cut a very thin sliver off the bottom of each bell pepper, just enough to even them off so that they sit standing up without wobbling. Make sure the bottom stays intact so that you have a solid cup that won’t leak.
Heat a large nonstick skillet over medium-high heat and add two tablespoons EVOO, about two turns around the pan. Add the chicken and season with salt and pepper. Cook until brown, about 5-8 minutes, breaking it up into small bits with the back of a wooden spoon as it cooks. Add the onion, garlic, piquillo peppers, raisins and paprika. Continue to cook until the onions start to get tender, about 3-4 minutes.
Deglaze the pan with the sherry, stirring to get any brown bits off the bottom of the skillet. Add 1 1/2 cans of tomato sauce and cook about five minutes more. Turn off the heat and add the parsley, almonds and cooked rice to the pot. Stir to combine.
Pour the remaining 1/2 can of tomato sauce into an ovensafe baking dish with a touch of water for additional liquid to create a bed for the peppers to sit on. Fill each pepper up halfway with the chicken and rice filling mixture.
Top with a little Manchego cheese. Fill with more chicken and rice mixture, then add a little more cheese on tip of that. Set in the baking dish and place the tops back on top of each pepper as a lid.
Bake, uncovered, for 20-30 minutes.