01 -
Preheat oven to 205°C and position a rack in the center. Lay pancetta slices over a cooling rack set atop a parchment-lined baking sheet, covering with another cooling rack to maintain flatness. Bake for 45 minutes, or until pancetta is crisp. Drain on paper towels and reserve 1 teaspoon of rendered fat.
02 -
While pancetta bakes, combine black pepper, egg yolks, parmesan, pecorino, and half the milk in a heatproof bowl. Whisk until smooth. Set up a double boiler and whisk the mixture over simmering water until thickened, about 5 minutes. Remove from heat, whisk to slightly cool, then incorporate remaining milk and reserved pancetta fat. Season with salt and set aside.
03 -
Decrease oven temperature to 150°C. Boil water for a bain-marie. Grease four 10-centimeter ramekins or one 20-centimeter square pan with butter. In a large bowl, whisk together Greek yogurt, milk, black pepper, and salt, then incorporate eggs and beat until fully blended. Fold in chives. Pour mixture into prepared ramekins or pan. Place inside a larger baking vessel and add boiling water until it reaches halfway up the sides. Bake for 30 minutes, rotating the dish halfway through. Cool slightly before unmolding or, if baked as a single batch, cut into four squares.
04 -
Slice buns and toast cut-side down in a lightly oiled skillet set over medium-high heat until golden brown.
05 -
To assemble, spread carbonara cream onto the bottom buns. Layer each with a slice of crisp pancetta, a soufflé egg square, a mix of the reserved parmesan and pecorino, and one raw egg yolk. Set the top bun in place and serve immediately.