Heat the milk and vinegar in a small saucepan until it simmers. Remove from heat. Add vegan butter and stir until melted. Let cool until lukewarm.
In a large mixing bowl add 2 ¼ cup flour, yeast, sugar, and salt. Stir to combine.
Add water to the cooled soy milk mixture. Stir to combine. Add this to the flour mixture. Stir to combine. It should be sticky at this point.
Add the remaining flour, ½ cup at a time, stirring well after each addition. Once the dough starts to form into a ball, knead the mixture in the bowl for about 5 minutes, sprinkling with flour to keep it from getting too sticky.
Spray the top of the dough ball with vegetable spray and cover with a damp cloth (or plastic wrap). Place in a warm place to rise for an hour (or so).
In the meantime, mix the filling ingredients by combining the brown sugar, cinnamon, and softened vegan butter in a small bowl. Stir to combine.
Roll out the dough into an 8x20" rectangle. Spread it with the cinnamon-sugar mixture. Note: you could add a sprinkling of raisins or finely chopped nuts here.
Starting at the far end, roll the dough toward you and pinch the final seem. Place this in your lightly greased loaf pan and cover and let rise until doubled, about 30 minutes.
When you're ready to bake, preheat the oven to 350°F/175°C. Grease a 9x5-inch loaf pan.
Place the loaf in the prepared pan and bake for 40 to 45 minutes, until the crust is lightly browned. Remove from the oven and set aside to cool.
Allow the bread to cool for 10 to 15 minutes. Store bread in a sealed container in the fridge for up to 5 days. To freeze, allow the bread to cool completely and then cut into slices. Place slices on a tray and place in the freezer. Once slices are frozen (about 30 minutes), transfer to a freezer bag. This bread will keep in the freezer for 1 month.