Moist and tender, but not too sweet, these bran muffins don't seem like a penance to eat. Although they're best the day they're made, these muffins can be stored in a closed container at room temperature for up to 3 days.
Position a rack in the lower third of the oven, and preheat to 375 degrees F.
To make the glaze, place the butter and sugars in a small bowl and beat until smooth. Add the boiling water and honey, and stir until the glaze is smooth and the sugar has dissolved. Using a pastry brush, generously coat the sides and bottoms of a 12-cup standard muffin tin with the glaze. Use all of the mixture.
Place the dates in the bowl of a food processor and pulse to chop. With the machine running, pour in the 1/4 cup of boiling water and process until the dates are puréed. Transfer the purée to a large bowl and add the honey and oil, beating to blend. Add the eggs and beat again to combine. Stir in the buttermilk.
In another bowl, whisk together the flour, baking soda, and salt. Add the bran to the bowl with the flour and whisk again to evenly distribute the ingredients. Add the dry mixture all at once to the bowl with the date batter and stir just to combine. Don't overmix!
Spoon or scoop the batter into the prepared muffin pan, filling each cup three-quarters full. Bake until the muffins are set and a toothpick inserted into the center comes out clean, 25 to 30 minutes.
Let the muffins cool in the tin for 5 minutes before inverting them onto a wire rack to finish cooling.