Beef Tartare with Roasted Bone Marrow

0 Roast the marrow. Preheat the oven to 450°F. Place the two marrow halves cut-side up in a roasting dish and season with salt. Roast for 15–20 minutes, checking from 15 minutes, until the marrow is soft and hot throughout but has not melted away.
1 Dice the beef. While the marrow roasts, finely dice the cold filet with a sharp knife. Transfer to a chilled mixing bowl.
2 Mix the tartare. Add the scallion, cornichons, Marcona almonds, Dijon, pasteurized egg yolk, soy sauce, and olive oil. Gently stir until the beef is evenly coated. Season lightly with salt and pepper, remembering that the mix-ins already contribute salt. Refrigerate until assembly.
3 Toss the salad. Just before serving, lightly dress the frisée with lemon juice, olive oil, and a pinch of salt. Add shaved Parmigiano and gently toss again.
4 Finish and serve. Spoon the tartare over the freshly roasted marrow. Top with the frisée salad and extra Parmigiano. Serve immediately with crusty bread.