Preheat oven to 350°. Spray a 9x5-inch loaf pan with nonstick cooking spray.
In a large bowl, combine flour, baking powder, baking soda, and salt. Stir in carrot puree, 1½ cups cheese, and thyme.
In a medium bowl, whisk together buttermilk, melted butter, and eggs. Add buttermilk mixture to flour mixture, stirring well to combine. Spoon batter into prepared pan. Sprinkle remaining ¼ cup cheese and pepper onto top of batter. Bake for 45 to 55 minutes or until a wooden pick inserted in center comes out clean. Let cool in pan for 10 minutes. Remove from pan, and let cool on wire rack.