Add the non-dairy milk, sugar, vegan butter, pumpkin puree, and vanilla paste to a small saucepan. Heat until warm, the temperature should be between 105-115F. If you don’t have a thermometer, I would recommend reading this article for tips on checking the temperature. Just be sure the liquid isn’t so hot that it kills the yeast. Once the mixture is within the correct temperature range, evenly sprinkle the yeast over the liquid. Stir to incorporate, then allow to sit for about 10 minutes. After ten minutes, you should see some bubbling on top. This indicates that the yeast is active.
Add 3 1/2 cups of the flour to a bowl, stir in the milk/yeast mixture with a spatula until mixed. The resulting dough will be very loose and sticky. Cover with a towel and set in a warm place for about an hour, or until the dough almost doubles in size.
In a separate bowl, whisk together the remaining 1 1/2 cups of flour, baking powder, salt, pumpkin pie spice, cinnamon, and nutmeg. Add the dough to the bowl of a stand mixer fitted with a dough hook. Add in the flour/spice mixture to the bowl and knead on medium speed to combine. Allow to knead for about 5 minutes, or until very smooth. The dough will be slightly sticky to the touch. If the dough feels too wet and sticky, add an additional 1/4 cup of flour. Just be sure not to add too much flour as this could result in the cinnamon rolls becoming really dense, the dough should be a little sticky to the touch. Note: if you do not have a stand mixer, you can knead the dough by hand. I recommend first kneading the dough in the bowl until you get the flour/spice mixture incorporated. Then, turn the dough out onto your very lightly floured counter. To knead, fold the dough in half and then press outwards. Repeat this movement for about 7-10 minutes, or until very smooth. I recommend watching this video for a visual on kneading the dough and checking to see if it’s properly kneaded. Turn the dough out onto a lightly floured surface, sprinkle with some additional flour. Using a lightly floured rolling pin, roll the dough out into a rectangle. The dough should be just under 1/2 inch thick. Square off the edges and try to make sure the shape is as rectangular as possible, this will make it easier to roll up and cut.
In a separate bowl, mix together all of the filling ingredients apart from the pecans. The mixture should be thoroughly combined and spreadable. Dollop spoonfuls of the filling mixture onto the surface of the rolled out dough. Spread out evenly over the dough, leaving a 3/4 inch border around the edges. Sprinkle the chopped pecans evenly over the filling.
Begin rolling the dough up lengthwise, keeping it as tight and even as possibly without squishing the filling. Once it’s fully rolled up, pinch the seams to seal. Use a knife to score the tops of the cinnamon rolls where you plan on cutting them. I cut mine into 12 even pieces.
Cut the cinnamon rolls. I like to use some plain dental floss to do this. You can cut a piece of dental floss and slide it under the log of dough, then tie it around the log and pull tight, it will cut the dough into a perfect spiral without squishing it. Alternately, use a very sharp knife. Place the cinnamon rolls into a buttered or sprayed dish of your choice. I used two 8x8 inch square baking pans and placed six rolls in each. Alternately you could use two 9 inch round pans, or you could place all 12 in a 9x13 inch pan. I like to leave just a little bit of space between the rolls to allow them room to grow on their second proofing.
Cover your baking dishes with a towel and set them somewhere warm for an additional hour or so, until they’ve doubled in size.
Preheat oven to 350 F. Place your baking pans on a center rack in the oven. Bake for 30-35 minutes, or until golden brown on top and cooked through.
Remove from the oven and allow to cool for about 10 minutes before frosting. Prepare the frosting by combining all of the frosting ingredients in a bowl and stirring until combined. Use the back of a spoon to spread the frosting over the warm cinnamon rolls.
Serve and enjoy!