Place the peas (soaked overnight) in the soaking water, cover, and simmer over medium-low heat for 45-60 minutes in a pressure cooker, or 1.5-2 hours in a regular pot, until very soft. Pass through a sieve or puree until smooth. Stir in some butter and enough hot meat or ham broth to reach a smooth consistency. Season with salt, pepper, or nutmeg to taste.
In a large skillet, melt 2½ tablespoons butter or cook 125 g diced bacon over medium heat. Increase heat to medium-high, add 2 diced onions, and cook for 5-8 minutes, stirring frequently, until crispy and golden brown. Pour this mixture over the pea puree.
In a large pot, heat 1 tablespoon lard over medium heat. Add 300 g sauerkraut and break it up with a fork. Pour in 1½ cups white wine. Add 1 bay leaf and some juniper berries. Reduce heat to medium-low and simmer for 20-30 minutes, stirring occasionally, until very soft. Add more wine if needed. Just before serving, stir in 1 cup drained pineapple.
In a large pot, bring 3 liters of water to a boil over medium-high heat. Add 3 grains of spice, some pepper grains, 1 bay leaf, 1 onion (halved), and soup greens to taste. Do not add salt. Add the pork knuckle (1 per person), ensuring it is fully submerged. Reduce heat to low and simmer gently for 2-3 hours until the meat separates easily from the bone and reaches an internal temperature of 63°C / 145°F. Taste the broth and adjust seasoning with salt, pepper, 1 teaspoon sugar, or 1 teaspoon vinegar as desired.
If desired, remove the cooked pork knuckle and grill briefly over medium-high heat for additional browning.
Serve the pork knuckle with the pea puree and sauerkraut alongside.