Add flour and cinnamon (if using) to a large bowl.
Gently fold in blueberries until they're coated with flour.
Pour in heavy whipping cream and gently stir with a large wooden spoon until all the flour is wet.
If some of the flour remains dry, add in a little more cream or milk. You want the dough moist and sticky but not sloppy wet.
Scoop out the dough with a standard size ice cream scoop. Place the scoops of dough 1 inch apart on a large baking sheet covered in parchment paper or a baking mat.
Sprinkle each biscuit with demarara sugar.
Bake in a 450 degree oven for 12 to 14 minutes or until the tops have started to brown.