- Combine the dates, walnuts, baking soda, salt, and xanthan gum (if using) in a medium bowl. Pour in the boiling water and stir in the butter. Let the mixture rest for 20 minutes.
- Preheat the oven to 350°F. Spray a 9 × 5-inch loaf pan with cooking spray.
- In a large bowl, stir together the applesauce, vinegar, and vanilla. Gradually stir in the flour and sugar.
- It will be lumpy, and that’s okay; just incorporate everything as thoroughly as you can. Add the date mixture and stir until combined. Pour into the prepared loaf pan.
- Bake for 50 to 55 minutes, until a toothpick inserted in the center comes out clean. Let cool in the pan for 15 minutes before transferring to a cooling rack.
- Cool for at least 4 hours before slicing. Leftovers can be stored in an airtight container at room temperature for 3 to 4 days.