Make the nogada sauce. Boil the water in a small pot over high heat. Add the walnuts, cover, and soak for 5 minutes to loosen the skin.
Using your fingers or a paring knife, carefully remove the papery walnut skin off each walnut and place the peeled, skinless walnuts in a bowl. This is a very tedious process and takes patience, but it's an important step to ensure the sauce doesn't come out bitter.
Add the skinned walnuts, goat cheese, queso fresco, milk, Mexican crema, ground cinnamon, and sugar to a blender. Blend for 5 minutes until completely smooth. Set aside.
Make the filling. Heat the olive oil in a large skillet over medium-high heat. Add the onion and cook for 3 minutes, stirring occasionally. Add the garlic and cook for 30 seconds.
Add the ground beef and ground pork. Cook for 6 to 8 minutes, breaking up the meat into small pieces as it cooks.
Stir in the tomato sauce, golden raisins, dried pineapple, salt, black pepper, ground cloves, and ground cinnamon. Cook uncovered for about 8-10 minutes, stirring occasionally, until the excess moisture is cooked out.
Reduce the heat to low and stir in the pear, apple, peach, plantain, and slivered almonds. Cover and cook for about 15-20 minutes, until the fruit is tender and cooked through. Set aside to cool slightly.
Prepare the poblanos. Line a large baking sheet with aluminum foil and place the poblano peppers on top. Set your oven rack directly underneath the broiler and turn the broiler on.
Broil the poblanos for 5 minutes or until the skin is blackened and blistered. Carefully flip them over and broil for another 5 minutes or until the skin is blackened and blistered.
Remove them from the oven and loosely cover the baking sheet with aluminum foil or plastic wrap to keep in some of the heat and help them steam. Let them sit for 5 minutes.
Peel and rub off as much of the loose skin on the peppers as possible. It doesn't have to be perfect; just as much as you can.
Cut a small slit down the middle of the peppers with a knife. Carefully scoop out and discard the seeds using a spoon.
Assemble the Chiles en Nogada. Carefully stuff the peppers with the picadillo filling. Some of the peppers will be extra fragile because of the roasting process and may tear – that's okay. Just do the best you can. The peppers do not need to fully close, so stuff them as much as you can. parsley.
Garnish and serve. Drizzle the nogada sauce over the peppers and garnish with pomegranate seeds, chopped parsley, and a sprinkle of flaky sea salt. Serve immediately.
Notes
Walnuts: Removing the skin from the walnuts is a very tedious process that can take up to 45 minutes, but it's an important step to ensure the sauce doesn't come out bitter.
Poblano peppers: This filling in this recipe fills up 6 large poblanos or 8 medium poblanos.