Step 1
Cut sweet potato in half lengthwise. Cut each in half again lengthwise then in half cross-wise. Cut each piece in half to make about 16 evenly sized chunks. Transfer into pot; cover with water and add salt. Bring to a simmer on high heat; reduce heat to medium-low and cook until potatoes are tender about 17 minutes. Drain thoroughly; return to pot and mash potatoes. You will need 1 1/2 cups mashed sweet potatoes. Cool thoroughly.
Step 2
Transfer cooled mashed potatoes to a mixing bowl. Add brown sugar and buttermilk. Mix together until well combined.
Step 3
Place self-rising flour in a separate mixing bowl. Grate frozen butter into flour tossing with a fork to coat with flour after each addition of about 1/3 to 1/2 stick. This will prevent butter from clumping. Mixture should look like floury pieces of butter. Add sweet potato mixture. Toss with a fork until evenly distributed but don't overmix.
Step 4
Transfer mixture onto a lightly floured work surface. Push and press mixture together into a rectangular shape about 1 1/2 inches thick. Dough will be floury and a bit crumbly. Fold rectangle into thirds lifting up one-third and folding onto the middle and doing the same with the other side. Dust with a bit of flour if sticking.
Step 5
Preheat oven to 425 degrees F (220 degrees C). Line a rimmed baking sheet with a silicone mat.
Step 6
Press dough into a rectangle again about 1 inch thick. Repeat the tri-fold step. Press out into a rectangle about 1 inch thick. Trim off the rough edges to square off the sides; this will maximize rising. Cut into 8 equal portions. Transfer to prepared baking pan spacing biscuits evenly. Brush tops lightly with 1 tablespoon melted butter.
Step 7
Bake in preheated oven until browned 20 to 25 minutes. Cool slightly before serving.
Step 8
Mix 4 tablespoons butter (room temperature) pomegranate syrup and pomegranate juice together in a small bowl. Spread on warm biscuits. Sprinkle with a few pomegranate seeds for garnish.