Step 1

Preheat your oven to 300°F (150°C).

Step 2

Place the bone marrow segments on a baking sheet. You might want to place them on a wire rack for better airflow.

Step 3

Roast the bone marrow in the preheated oven for about 40 minutes until they are softened and slightly golden. This will infuse the marrow with a smoky flavor.

Step 4

Once the bone marrow is roasted, remove it from the oven and allow it to cool slightly.

Step 5

Collect any drippings that have accumulated on the baking sheet. If needed, add enough neutral oil to the drippings to yield a full cup of oil. This oil will be the base of your mayo.

Step 6

In a clean and dry jar or bowl, combine the egg yolks, Dijon mustard, white wine vinegar, and lemon juice.

Step 7

Use a hand blender or immersion blender to blend the egg yolk mixture while slowly drizzling in the bone marrow-infused oil. Start with a slow drizzle and gradually increase the speed as the mayo begins to emulsify.

Step 8

Blend until the mixture thickens and emulsifies into a creamy mayonnaise consistency. This should take a few minutes of blending.

Step 9

Season the mayo with salt and pepper to taste. Remember that the bone marrow drippings might already contain some salt, so be cautious.

Step 10

Taste the mayo and adjust the seasoning, adding more salt, pepper, or lemon juice if desired.

Step 11

Transfer the bone marrow mayonnaise to a clean jar or airtight container.

Step 12

Refrigerate the mayo for at least an hour before using to allow the flavors to meld together.