In a large bowl, whisk together the flour, baking powder, baking soda, and salt. In a separate bowl, whisk together the egg, honey, applesauce, milk, vegetable oil, and vanilla extract until smooth.

Pour the wet ingredients into the dry ingredients and stir just until combined; a few small lumps are fine. Don't overmix, or the muffins will turn out dense.

Fold in the chopped dates. Divide the batter evenly among a greased or paper-lined 12-cup muffin tin, filling each cup about two-thirds to three-quarters full.

Bake in the center of a 375°F (190°C) oven for 18 to 20 minutes, until a toothpick inserted into the center of a muffin comes out clean.

Let the muffins cool in the tin for 5 minutes, then transfer to a wire rack to cool completely (or enjoy warm).