To prepare the Boiled Beef: In a stockpot, melt the butter over medium heat. Add the onions, celery, carrots, parsnips, and leeks and saute them just until glossy, 3 to 5 minutes. Add the bay leaves, peppercorns, allspice, and beef stock. Bring to a boil, skimming away the froth that rises to the surface. Add the beef and reduce the heat to a simmer. Season with salt and pepper. Cook the beef until tender, 2 to 3 hours.
Remove the beef from the stockpot and let it rest for 15 minutes. Cut the meat crosswise, against the grain, into 1/2-inch-thick slices. Spread a thin layer of mustard on one side of each slice of beef. On a plate, stir together the breadcrumbs and minced parsley. Dip the mustard side of the beef slices into the mixture and press to thickly coat with crumbs.
In 2 separate saucepans, gently reheat the Pickled Vegetables and Pickled Pumpkin. In each of 2 separate medium saute pans, heat 2 tablespoons of oil over medium heat. Carefully place the beef slices in the pan, crumb side down, and saute until golden in color, 30 seconds to 1 minute. With a spatula, carefully turn the slices over and cook just until reheated, 30 seconds to 1 minute more.
To serve, place a generous spoonful of the heated pickled vegetables and pumpkin on each heated serving plate. Arrange 2 to 3 slices of beef on top, crumb-sides up. Drizzle pumpkin seed oil around the beef slices and sprinkle with toasted pumpkin seeds. Garnish with alfalfa sprouts or micro greens. Serve immediately.
To make the Pickled Vegetables: In a large saute pan, heat the olive oil over medium heat. Add the onions and shallots and sweat them for 1 to 2 minutes. Add the red and yellow bell peppers and zucchini and cook until the onions are translucent, 3 to 4 minutes more. Add the vinegar and stir and scrape to deglaze the pan deposits. Add the bay leaves, rosemary, honey, and water. Bring to a boil, stirring frequently. Season, to taste, with salt and pepper. Spoon the mixture into a sterilized jar, cover, and refrigerate for at least 3 days.
To make the Pickled Pumpkin: In a large saute pan, heat the olive oil over medium heat. Add the shallots and sweat them for 1 minute. Add the pumpkin and cook for 2 minutes more. Add with vinegar and stir and scrape to deglaze the pan deposits. Add the bay leaves, rosemary, honey, and water. Bring to a boil, stirring frequently, and simmer just until the squash cubes are al dente, about 15 minutes. Season, to taste, with salt and pepper. Spoon the mixture into a sterilized jar, cover, and refrigerate for at least 3 days.