Oregon Blue Vein Buttermilk Biscuits

2 1/2 cups unbleached all purpose flour or whole grain pastry flour
2 teaspoon baking powder
3/4 teaspoon coarse salt
1/2 teaspoon baking soda
2/3 cup chilled solid vegetable shortening, cut into 1/2 inch cubes
1 cup crumbled Oregon Blue Vein cheese
1 tablespoon chopped fresh chives
1 tablespoon chopped fresh thyme
1 cup plus 1 tablespoon buttermilk
ground black pepper

Preheat oven to 350. Line baking sheet with parchment paper. Whisk first 4 ingredients in medium bowl to blend. Add shortening; using fingertips, rub in until coarse crumbs form. Mix in 3/4 cup cheese, chives, and 1 1/2 tsp thyme. Make well in center; add 1 cup buttermilk and stir until dough forms, gradually mixing in dry ingredients. Turn dough out onto floured surface. Knead gently until combined. Pat dough into 1 inch thick rectangle. Cut into 8 squares. Transfer squares to baking sheet. Brush with 1 tbls buttermilk. Sprinkle with 1/4 cup cheese, 1 1/2 tsp thyme and pepper. Bake until golden brown, about 20 minutes.