For the pozole broth:
Add the water in a pot over high heat. Add the chicken thighs and/or drumsticks to the pot. Adjust the heat level to keep the broth at a gentle simmer. Using a spoon, skim and discard any froth or foam that rises to the surface of the broth. Cook for about 1 hour.
While the chicken simmers, preheat the oven to 400°F. Line a half sheet with oven paper. Set the pork bones on the baking sheet and roast for 30 minutes, or until the bones are golden brown.
Transfer the roasted pork bones to the broth. Add the bacon and adjust the heat level to keep the broth to a simmer. Using a spoon, skim and discard any froth or foam that rises to the surface of the broth and replenish with water to keep the broth at the same level throughout. After 45 minutes, fish out the bacon and discard it. Continue simmering the pork meat and bones for 1 hour, replenishing the water as needed. Add the green onions, onion, and carrot to the pot, and simmer for 1 hour more.
Remove and discard spent bones and vegetables. Pass the broth through a chinois. Pour the broth back in the pot.
For the green bechamel seasoning:
In a saucepan, melt the butter over medium heat. Add the masa flour and whisk constantly until a smooth paste, known as a roux, forms.
Gradually pour in the milk while whisking continuously to prevent lumps from forming. Continue whisking the sauce over medium heat until it thickens and reaches a creamy consistency. In a blender blend in the spinach and chiles.
Season with salt, pepper, oregano and nutmeg. Taste and adjust the seasoning according to your preference.
Season the pozole broth:
Stir the green bechamel seasoning into the broth. Taste and adjust to your taste.
For the braised pork shanks:
In a large, sturdy resealable plastic bag, combine the masa and chile powder with 1 tablespoon each of salt and pepper and shake to coat thoroughly.
In a large skillet, heat 2 tablespoons of the olive oil until it shimmers. Add the pork shanks and cook over moderately high heat until browned all over, about 10 minutes. Transfer the browned shanks to a 5 qt. braiser.
Add the onion, carrots, celery, and garlic to the skillet and cook over moderate heat until softened, about 5 minutes. Add the mezcal and carefully flambee the alcohol out of it. Simmer until slightly reduced, about 2 minutes. Pour the mezcal and vegetables over the pork. Add the stock, rosemary, bay leaves, and thyme; season with salt and pepper and bring to a boil. Tuck the pork shanks into the liquid so that they're mostly submerged. Cover and cook over moderately low heat for 2 1/2 hours, or until the meat is very tender. Turn the pork shanks every 30 minutes to keep them submerged in the liquid. Transfer the braised shanks to a large, deep platter; cover and keep warm.
Strain the liquid, pressing hard on the solids; discard the solids. Return the liquid to the braiser and boil until reduced to 4 cups, about 20 minutes. Spoon off the fat and reserve.
To serve:
Finish cooking the heirloom corn kernels in 1/3 of the pozole broth until it's tender to your liking, about 10-15 minutes.
In a deep dish/plate, lay a bed of the kernels and slightly submerge with stock.
On the side, glaze the pork shanks with a bit of the pork gravy and carefully place over the slightly submerged kernels. Decorated around the shank with radish slices, purslane and edible flowers. Serve with lime wedges to be able to adjust the acidity of the plate to your personal taste.