Prep ingredients: Bring a medium pot of salted water to a boil. Peel and finely chop all of the shallot. In a medium bowl, combine cranberries, ½ cup water, 1 tablespoon sugar, and a pinch each salt and pepper. In another medium bowl, whisk together 1 cup water, broth concentrate, mascarpone and 1 tablespoon flour.
Cook cranberry relish: Heat 1 tablespoon oil in a medium nonstick skillet over medium-high. Add half of the shallot; cook until softened, about 2 minutes. Add cranberry mixture, bring to a simmer, and cook until mixture is thick and jammy and reduced to ½ cup, 5-7 minutes. Coarsely mash cranberries with a fork; transfer to same bowl and cover to keep warm. Rinse and dry skillet.
Cook meatballs: In a medium bowl, combine panko, remaining shallot, 1 large egg, ¾ teaspoon salt, and ¼ teaspoon pepper. Add beef and knead or stir to combine. Form mixture into 10 meatballs. Heat 1 tablespoon oil in reserved skillet over medium-high. Add meatballs and cook turning once or twice, until browned but not cooked through, 6–8 minutes.
Add sauce: Remove from heat, tilt the skillet and spoon off and discard as much excess fat as possible. Return pan to medium-high, then add mascarpone mixture. Bring sauce to a simmer and continue to cook, basting meatballs with a spoon until sauce is reduced to 1 cup and meatballs are cooked through, 6–8 minutes.
Cook noodles: While sauce simmers, roughly chop dill. Add ¾ of the noodles to boiling water (save rest for own usand cook until tender, 5–6 minutes. Stir in peas and cook, about 2 minutes more. Drain. Return peas and noodles to pot and stir in 2 tablespoons butter and half of the chopped dill.
Serve: Spoon noodles into shallow bowls and top with meatballs and sauce. Serve topped with remaining dill and cranberry relish alongside.