In a large bowl for a stand mixer, combine flour, sugar, yeast, and salt.
Turn stand mixer onto low and add in the water.
Once ball is formed, grease the same bowl mixed in and place the dough ball back into the bowl.
Cover with a towel or plastic wrap and let sit for 60-90 minutes in a warm, draft free place until doubled.
While this is rising, chop all your vegetables.
In a large skillet over medium heat, add your vegan butter.
Once melted, add in the diced onions and mushrooms. Let saute for 2-3 minutes until softened.
Add in the garlic and sun dried tomatoes and let cook for another 2 minutes. Stirring often.
Sprinkle the salt, pepper, and red pepper flakes over top and combine again.
Add in the spinach and stir together until it has wilted down, about 3 minutes.
Low heat and add the chickpea flour. Stir to combine until no powder remains.
Add in the milk and stir to combine. Let this cook down until the mixture has thickened and is no longer saucy. Stirring often.
Remove from heat and let cool completely before adding it to the dough.
Once dough has doubled in size, pull out the dough and lay it out on a lightly floured surface.
Using a rolling pin, roll dough into an approximately 17×25″ rectangle that is 1/4″ thick.
Spoon the mushroom mixture evenly over the dough. *Do NOT add hot mixture to dough.
Sprinkle the vegan parmesan cheese evenly across the top.
Carefully roll the dough into a log from the longest side up. One completely rolled, place seam side down. Cut into 12 even sized pieces.
Place into a greased 9x13 baking dish and cover to rise for 45-60 minutes.
Preheat to 350 degrees F.
Brush the tops with vegan butter (or dairy free milk if oil free).
Once heated, place dish inside and bake in oven for 30-35 minutes.