In a large bowl, heat the milk until it is just warmer than room temperature--be sure it's not too hot. Mix in the maple syrup. Add the yeast and let it sit for 5-10 minutes until it "blooms" or activates and becomes bubbly/foamy.
Whisk in the pumpkin puree, oil, and flaxseed meal. Once fully combined, fold in the salt, baking powder, white whole wheat flour, and ¾ c of the all-purpose flour. Cover the bowl and set aside in a warm place to rise for an hour.
In the meantime, make the filling. If you are using the option listed in the ingredient section (with coconut sugar), simply whisk together all the filling ingredients. If you are using the date version, follow the directions in the notes section. (the pictured filling is the date version).
Once the dough is done rising it should be about double in size. Fold in another ¾ c all-purpose flour, then transfer to a floured surface. Use the remaining ½ cup of flour as needed (you may need more or less) to knead. Knead the dough for 5-10 minutes. Do NOT keep adding flour until the dough is dry; only add flour if it is really sticking to the counter/surface.
Make sure the surface is well-floured so it doesn't stick, then roll the dough (make sure your rolling pin is floured too). Roll until it is about ½" thick. Please take note that the photo shown is only about half the dough; all of it wouldn't have fit in the frame.
Cut off the edges to make them super clean. You can use the scraps to make more later. This is optional, but it will result in the best-looking rolls. Spread the filling evenly throughout. If you are using the date filling, make the layer fairly thin, otherwise the date flavor can be overpowering; you will probably have some leftover.
Grease 2 9"x 11" (or any similar size) pans and set aside.
You can roll and cut the traditional way, but I find this method much easier and has a better-looking result: Cut the dough while it's flat, about 1" thick slices. Roll each slice individually and transfer to the prepared pan. Try not to pack them too closely; they will spread out. If using 9"x 11", you can fit about 6. Cover and let them rise for 30 minutes in a warm place.
Preheat oven to 350 degrees Fahrenheit.
While the rolls are rising, make the icing (optional, they taste great by themselves). In a small bowl, add the powdered sugar and whisk to remove clumps. add half of the milk and whisk until smooth. Add the cashew butter with the rest of the milk and lemon juice. Whisk until smooth.
Once the rolls are done rising, bake in the preheated oven for about 20 minutes (depending on size and how fast your oven cooks). Serve warm with the icing or alone. If you aren't planning to finish them on the first or second day, freeze as soon as it cools, and microwave to reheat.