Preheat your oven to 350 degrees and spray a 9 by 5 bread pan with cooking spray.
Combine 1 cup of the muesli with the buttermilk in a medium size bowl and soak while preparing the other ingredient, about five minutes.
In a large bowl, whisk together the flour, baking bowser, baking soda, salt, cinnamon, nutmeg, and allspice.
In a smaller bowl, beat the eggs. Then whisk in the brown sugar, pumpkin, oil, and vanilla. Gently stir the wet ingredients into the dry ingredients until just combined. Pour the batter into the loaf pan, top with the remaining two tablespoons of muesli and bake for about 55 minutes.
Cool in the pan for 15 minutes than transfer to a cooling rack to cool for an hour before slicing. Store in an airtight container for up to four days.