To Make the Dough:

1. Combine the flour, sugar, and salt in a large bowl (use the bowl of your stand mixer if you have one) and mix to combine. Mix in the yeast. Add the lukewarm nondairy milk and the melted vegan butter and mix to create a shaggy dough using a large wooden spoon.
2. If you have a stand mixer, mix using the dough hook on low speed for 7-8 minutes, until smooth. If you are kneading by hand, dump the dough onto a lightly floured solid surface and knead for 10-12 minutes, until smooth. The dough should be tacky but not terribly sticky.
3. Oil your hands with nonstick spray, then remove the dough from the bowl and form into a ball by stretching it from the sides around to the bottom. Spray the bowl with oil, then place the dough in the bowl seam side down. Spray the top of the dough, then cover the bowl tightly with plastic wrap.
4. Let rise in a warm place for 60-90 minutes, until doubled in size.

To Form the Rolls:

1. Combine the granulated sugar, cinnamon, and flour for the filling in a small bowl. Grease an 8-by-12-inch baking dish with nonstick cooking spray.
2. When the dough is done rising, use some more of the cooking spray to grease a solid work surface and dump the dough out of the bowl. Use a rolling pin to roll into a large rectangle that is 12 inches by 15 inches.
3. Use a silicone pastry brush to spread a thin layer of almond milk on top of the dough, then sprinkle the filling all across the surface, leaving a 1/2-inch border on one short side to help the edges seal together.
4. Roll the dough from the short edge into a tube. When you reach the edge that isn’t covered with the filling, pinch the seam to seal.
5. With a sharp knife, slice the roll into 10 even pieces and arrange in the baking dish with about 1 inch between rolls.

To Rise and Bake:

1. Cover the dish with plastic wrap and refrigerate overnight, or for at least 8 hours.
2. The next morning, remove the dish from the fridge (the portioned dough should have gotten a bit puffy) and set aside for 30 minutes. While the rolls rest, preheat oven to 350°F.
3. Remove the plastic wrap. Bake for about 30 minutes, rotating halfway thorough, until golden brown.

To Decorate:

1. While the rolls bake, combine the ingredients for the frosting, starting with just 3 tablespoons of the non-dairy milk. Stir, then add more milk as necessary, 1 teaspoon at a time. If you accidentally add too much liquid, just stir in more powdered sugar.
2. When the rolls are done baking, remove from the oven and let sit 5 minutes. Drizzle the rolls with the frosting and serve immediately.