Steps
1. Preheat the oven to 450°F (230°C).
2. Place the marrow bones upright on a baking tray or in a roasting pan.
3. Roast the bones for 15-20 minutes, until the marrow is soft but not melted away.
4. While the marrow roasts, brush the baguette slices with olive oil and toast them in the oven or on a grill until golden brown.
5. Remove the bones from the oven and let them cool slightly.
6. Use a small spoon to scoop out the marrow and spread it generously over the toasted baguette slices.
7. Sprinkle with chopped parsley, lemon zest, sea salt, and black pepper.
8. Serve immediately while warm and enjoy the rich, buttery flavor complemented by the fresh garnishes.