Cook bacon or pancetta in a large skillet over medium-low, stirring occasionally, until browned and fat has rendered, about 10 minutes. Transfer to a paper towel-lined plate, reserving 1 tablespoon drippings in skillet; discard or reserve remaining drippings for another use. Set bacon or pancetta aside.
Add olive oil, garlic, and pepper to reserved drippings in skillet; cook over medium, stirring constantly, until fragrant and garlic is beginning to brown, about 2 minutes. Stir in beans and ⅔ cup water; bring to a simmer over medium. Cook, stirring occasionally, until just heated through, about 3 minutes. Remove from heat, and let cool slightly for 1 minute.
Whisk together egg yolks, egg, Parmigiano-Reggiano, and miso in a small bowl. Stir egg mixture into cooled bean mixture, and toss off heat, until cheese is melted and sauce has thickened, about 1 minute. Divide mixture evenly among 4 bowls; top with reserved cooked bacon. Garnish with parsley, additional olive oil, black pepper, and Parmigiano-Reggiano. Serve with lemon wedges.
