For the sweet potato biscuits, preheat the oven to 400°. Line a 10- by 15-inch rimmed baking pan with parchment paper and dust it lightly with flour.
In a large mixing bowl, whisk together dry ingredients and the fresh thyme.
Cut the butter into roughly pea-sized cubes, refrigerate 5 minutes to get the butter cold again, then toss into the flour mixture, using your fingers to distribute the butter throughout the flour mixture (or use a pastry cutter or fork).
Stir in ¼ cup milk. Add the sweet potato, then work it into the dough using a sturdy spoon or spatula. Form the dough into a ball, then place the dough on the parchment paper. Dust your hands with flour and flatten the dough into a 12-inch round, approximately 1½ inches thick. Use a 2½-inch biscuit cutter to cut 8 biscuits, folding any scraps together as needed to use up all the dough.**
Place the biscuits at least 2 inches apart on the parchment paper, then brush them lightly with remaining milk. Bake until the biscuits are golden brown, 20 to 22 minutes. Remove them from the oven and allow to cool for at least 5 minutes before serving.
For the Ginger-Turkey Burgers, grate half of the onion on a box grater and discard any accumulated liquid. Slice the other half in ¼-inch lengths.
Heat olive oil in a medium saute pan, then add the sliced onion and saute until translucent, 5 to 7 minutes. Add the brown sugar, stirring well, and cook until the sugar has dissolved, approximately 2 minutes. (Caramelized onions may be made ahead of time and reheated.)
Combine the grated onion, ground turkey, breadcrumbs, ginger, soy sauce and red pepper flakes in a large bowl and mix gently to combine. Season with salt and pepper. Form into 4 patties and brush lightly with oil to prevent sticking. Heat the grill to medium-high and grill the burgers until cooked through, 5 to 6 minutes per side.
* To yield ¾ cup sweet potato flesh, pierce a 1-pound sweet potato all over with a fork, wrap it tightly in aluminum foil, place it in a baking dish, and roast at 350° until the potato is completely soft, approximately 1 hour 15 minutes to 1 hour 30 minutes. Allow the potato to cool completely, then scoop the flesh out of the skin with a spoon and discard the skins.
** If you don’t have a biscuit cutter, the dough can be formed into a 6- by 9-inch rectangle, approximately 1½ inches thick, then cut into 8 equal squares.
About this recipe
Total: $14.66 for 4 servings; $3.67 per serving.