Bloom yeast in warm water and honey. Mix all together and allow to sit until mixture is foamy.
Mix yeast mixture with remaining "wet" ingredients: pumpkin puree, buttermilk, egg, sugar, oil, and cinnamon.
When wet mixture is fully combined, add flour and salt, and mix using the hook attachment until combined.
Coat dough/bowl in neutral oil and leave to rise until doubled, about 2 hours.
To make filling, mix softened butter, cinnamon, and brown sugar until combined. Set aside.
After dough has doubled, split in half and roll out into an approximate 12" x 18" rectangle.
Spread half of the filling mixture evenly onto the rectangle.
Cut the rectangle into 3" x 3" squares. You should have 24 squares.
Stack squares in loaf pan.
Repeat with with second half of dough.
Let rise additional 30 minutes.
Bake for 15-20 minutes at 400F until lightly browned and fluffy.