1. Place the egg yolks in a tall, narrow container or jar. 2. Slowly drizzle in softened beef tallow while blending with an immersion blender. 3. Hold blender at bottom of jar until mixture begins to emulsify, then move upward. 4. Add sea salt and blend briefly to incorporate. 5. Taste and adjust salt or texture as needed. 6. Transfer to a clean jar and refrigerate immediately. 7. Let sit at room temperature a few minutes before each use.