Preheat your oven to 350°F (175°C) and prepare your muffin tin.

In a medium bowl, whisk together the all-purpose flour, whole wheat flour, granulated sugar, baking powder, baking soda, salt, and ground cinnamon.

In a larger bowl, whisk the eggs until frothy, then add the melted butter, buttermilk, orange juice, orange zest, and vanilla extract, mixing until smooth.

Gradually add the dry ingredients to the wet ingredients, stirring gently until just combined.

Gently fold in the chopped dates and optional walnuts or pecans.

Scoop the batter into the prepared muffin cups, filling each about two-thirds full.

Bake for 18 to 22 minutes, until a toothpick comes out clean.

Let the muffins cool for about 5 minutes in the pan before transferring to a wire rack.