Preheat the oven to 325 F (160 C)
Prepare a muffin tin with muffin liners or grease it with cooking spray.
Add all the dry ingredients (oats, flour, baking soda, salt, spice mix) to a large bowl. Whisk to combine.
In a separate mixing bowl, combine the canned pumpkin, brown sugar, milk, melted butter, honey, vanilla, and egg. Whisk until combined and smooth.
Push the dry ingredients to the edges of the bowl to create a space for the wet ingredients in the middle of the bowl. Add the wet ingredients and mix with a spatula until just combined. The mixture will seem on the more wet/moist side and that's ok!
Using 1/4 cup measuring cup, add the batter to the muffin tin. Sprinkle oats on top (if desired). Bake for 25-30 minutes, until the muffins are browned and a toothpick inserted comes out clean.