Begin by preheating your oven to 350 degrees Fahrenheit (175 degrees Celsius). Prepare a 12-cup muffin pan by greasing it or lining it with paper liners. Place the raisins in a small bowl, covering them with hot water, and allow them to soak for several minutes to become plump.

In a large mixing bowl, combine the whole wheat flour, brown sugar, pumpkin pie spice, baking powder, baking soda, and salt. Create a well in the center of the dry ingredients, then add the eggs, pumpkin purée, vegetable oil, and honey into this well. Mix the ingredients gently until the dry components are just incorporated.

After draining the excess water from the raisins, fold them along with the chopped walnuts into the muffin batter. Spoon the mixture into the prepared muffin cups, filling each cup approximately two-thirds full.

Bake the muffins in the preheated oven until the tops spring back when lightly touched, which should take around 18 minutes. Once baked, allow them to cool in the pan before removing them from the cups.