Stir yeast and brown sugar into warm water, allow to stand for 10 minutes – it should get very bubbly.
In a large mixing bowl, combine about half the flour and salt. Pour in yeast mixture, pumpkin, and vanilla, stir well to combine. Add remaining flour, combine. Dump dough out onto a floured surface, knead until soft and elastic, 5-10 minutes. (OR: mix it in a stand mixer with a dough hook for 5 minutes or so!)
Once dough is fully kneaded, place in a greased bowl, cover with plastic wrap, and allow to rise for one hour, or until doubled in size.
Once dough has doubled in size, roll out on a floured surface. Aim to make it a large rectangle, say 20 x 12″ or so.
Combine melted butter and maple syrup, evenly brush over dough, leaving a 1″ border around the edge. Combine brown sugar and spices, sprinkle evenly over the butter/maple syrup mixture. Sprinkle chopped walnuts evenly over sugar mixture. Starting with one of the shorter edges, tightly roll the dough up.
Generously grease a 9 x 13″ baking pan with extra butter or pan spray, sprinkle with sugar.
Using a very sharp knife, slice the roll into 6 even rounds. Carefully place each roll into the pan, spacing them evenly.
Cover pan with plastic wrap, allow to rise one more time – about 45 minutes. While waiting for the buns to rise, heat oven to 375F. Once final rise is over, pop the pan in the oven and bake for 35-40 minutes, or until golden brown and perfect.
As buns are baking, make the glaze: