Spaghetti night just got an upgrade. When tossed with pasta and savory stock, uni melts into a creamy carbonara sauce with a texture as velvety as custard.
Bring a large stockpot of water to a boil. Meanwhile, heat 2 tablespoons oil in a large skillet over medium; add garlic, and cook, stirring constantly, until light golden, 1 to 2 minutes. Add panko and 1/4 teaspoon of the salt; cook, stirring occasionally, until toasted, about 5 minutes. Transfer panko to a plate; wipe skillet clean.
Lightly whisk eggs, egg yolk, and cheese in a medium bowl; set aside. Add remaining 1/2 tablespoon oil to skillet, and heat over medium. Add bacon; cook until rendered and just beginning to crisp, about 7 minutes. Reduce heat to low to keep warm.
Add remaining 2 teaspoons salt to the boiling water; add pasta, and cook until al dente, about 12 minutes. Drain pasta, reserving 1 cup cooking water. Add pasta and 1/4 cup of the reserved cooking water to skillet; toss to coat. Remove from heat.
Add egg mixture and 2 ounces of the uni to skillet, stirring until uni dissolves into sauce. Stir in up to 3/4 cup reserved cooking water, 1/2 cup at a time, until desired consistency is reached. Stir in lemon juice; top with pepper, parsley, panko mixture, and remaining uni. Serve immediately.