Season pork shoulder with salt and pepper. Roll up and tie with kitchen twine at 2” intervals. (This helps keep the meat intact while cooking and makes for round, compact slices.)
Heat oil in a large heavy pot (at least 8 quarts) over medium-high heat Cook pork shoulder, turning, until brown all over, 10–12 minutes. Add scallions, garlic and ginger. Add the soy sauce and mirin, and stir to combine. Cook for another minute. Add the stock, cover, and bring to boil. Reduce heat, simmer, skimming the surface occasionally until pork shoulder is tender in about 2 1/2 to 3 hours. Remove the lid, and let simmer uncovered for 5 minutes, then add the tofu. Simmer gently for another 10 minutes, and season with salt, to taste.

Make the soft-boiled eggs: Fill a pot with enough water to cover the eggs, and bring to a boil. Gently lower the eggs (still cold from the fridge) into the boiling water, and let simmer for 7 minutes (for a slightly-runny yoke) or 8 minutes (for a soft, but set-up yoke).

Meanwhile, fill a large bowl with ice water. When the timer finishes, transfer the eggs to the ice bath to stop the cooking process. Wait at least 5 minutes, or until cool enough to handle, then carefully peel away the shell and slice in half, lengthwise. Set aside until ready to serve.

Assemble the ramen bowls: Meanwhile, chop the scallions and jalapeño (if using). Slice the pork into thin pieces. Set aside. When the eggs finish cooking, add the ramen noodles to the boiling water. Cook for 2-3 minutes, until soft, then divide the noodles into two large bowls. Add the sliced pork and the ramen broth. Top with the fresh scallions, jalapeño and the soft boiled egg. Serve immediately.