Preheat oven to 400° In medium bowl, mix baking powder, soda, thyme, salt and 2 cups flour. With pastry blender or 2 knives, cut in butter until it resembles coarse crumbs. Stir in cheese. In small bowl, with fork, beat eggs and 1/2 cup buttermilk. Stir buttermilk mixture into flour mixture just until ingredients are blended. Turn dough onto lightly floured surface; sprinkle top of dough lightly with flour. With floured hands, gently knead dough 15 times, sprinkling dough with additional flour if needed. Shape dough into a slightly flattened ball, about 7" across; cut into 8 wedges. Place scones on large ungreased cookie sheet, about 2" apart, If you like, brush tops lightly with buttermilk. Bake scones 18-20 minutes until golden. Serve scones warm or cool on wire rack to reheat later.