Preheat the oven to 450F.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. Then add the blueberries and toss until evenly dispersed. Set aside.
In a separate medium bowl, whisk together the buttermilk, Greek yogurt, and vanilla until well combined.
Make a well in the center of the flour mixture, and pour in the wet mixture. Use a wooden spoon or spatula to stir until just combined, being careful not to overwork the dough.
Add the butter to a baking pan and place it into the oven to melt.
Prepare the cinnamon crunch topping by mixing the brown sugar and cinnamon together in a small bowl.
Remove the pan from the oven and pour/drop the biscuit dough into the hot butter. Spread the dough evenly out to the edges of the pan.
Score the unbaked dough into 6 or 8 equal rectangles or squares.
Sprinkle the cinnamon brown sugar all over the tops of the biscuits.
Bake at 450F for 25-30 minutes, or until the biscuits are deeply golden, crispy, and bubbling.
Remove the biscuits from the oven and let rest for at least 5-10 minutes before serving.
