Preheat the oven to 400 degrees.

Prepare a 9x13 baking dish with nonstick cooking spray.

In a large mixing bowl, beat the egg.

Add the sour cream and whisk until well combined.

Add the butter to the sour cream mixture and stir until combined.

Mix the flour, sugar, baking powder, baking soda, and salt and stir until well mixed.

Turn the shaggy dough out onto a lightly floured surface.

Using well-floured hands, knead the dough a few times and shape the dough into a rectangle. Roll the dough until about 1 inch thick.

Using a biscuit cutter, press straight down into the dough without twisting (to avoid sealing the dough.)

Place the biscuits into the prepared baking dish. Reshape the dough and continue cutting the biscuits until all of the dough is used.

Bake the biscuits for 15 to 20 minutes or until the tops begin to brown.

Prior to serving, brush the warm biscuits with melted butter if desired.