Cut in the butter until it resembles coarse meal. Stir in the buttermilk until just combined. Using an ice cream scoop or large spoon, scoop the dough on top of the blueberries.
1/2 cup (114g) cold unsalted butter, 3/4 cup buttermilk
In a pinch bowl, mix together the sugar and cinnamon and sprinkle the mixture on top of the biscuits.
1 Tbsp granulated sugar, 1/2 tsp ground cinnamon
Bake for 45-50 minutes or until the biscuits are golden and cooked through.
Notes
Leftovers can be covered and stored at room temperature for up to a day or in the fridge for up to 3 days.*homemade buttermilk - add 2 tsp of white vinegar or lemon juice to a liquid measuring cup and fill to 3/4 cup with milk of choice. Stir and let stand for 5 minutes.