Grate the frozen butter into the sifted self-rising flour. Add sugar. Stir to combine until the butter is fully coated by flour. 

Put the bowl in the freezer for 10 minutes 

Combine buttermilk to bring together as a dough. Stir no more than 15 times. Overworking the dough at this stage could cause your finished biscuits to be tougher.  

On a floured surface, dump out the dough and roll it with a rolling pin. Dust with flour as needed when the dough gets sticky. Fold the dough over on itself five different times, creating layers. Each time you fold, add some blueberries. The point here is to get them incorporated into your dough without smashing them to bits. 

Roll the dough to about 1/2 inch thick.

Cut biscuits into circles or squares and place on a parchment-paper-lined baking sheet. When cutting, you do not want to twist the cutter. Twisting while cutting will ruin the layers that you created with folding. 

Placing your cut biscuits next to each other (touching) on the sheet pan will help them rise taller. 

Bake at 475 F (247 C) for around 15 minutes. Check around the 12-minute mark to make sure they do not brown too much. 

When the biscuits are done, transfer them off of your baking pan onto a cooling rack to stop the bottoms from cooking further. Paint the melted butter on top of each biscuit or you can prepare a glaze if you want them to be more like the bo-berry biscuits at Bojangles.  

(OPTIONAL) To make the optional glaze, combine all ingredients in a saucepan over medium-low heat. Whisk until fully combined. Spoon over biscuits right before serving.