1/2 cup whole-wheat pastry flour, plus additional for dusting
5 tbsp oat flour
1/2 tsp plus 1/8 tsp sea salt
1/4 cup cold coconut oil
1 tsp extra-virgin olive oil
1/2 lb cremini mushrooms, diced
1/2 cup diced onion
1/8 tsp ground black pepper
2 oz goat cheese
2 tsp chopped fresh flat-leaf parsley leaves
2 tsp chopped fresh mint leaves
Olive oil cooking spray
4 5-oz boneless, skinless chicken breasts
Into a large bowl, sift flours and 1/2 tsp salt. Using a fork, cut in coconut oil until mixture is crumbly and has the texture of wet sand. Add 3 to 4 tbsp ice-cold water, 1 tbsp at a time, mixing until a soft dough forms. Form dough into a ball and flatten into a disc. Wrap disc in plastic wrap and refrigerate for 20 minutes.
In a medium skillet on medium, heat olive oil. Sauté mushrooms until soft, 2 to 3 minutes. Add onion and pepper; sauté 4 to 5 minutes more. Stir in remaining 1/8 tsp salt. Remove skillet from heat; set aside.
In a small bowl, combine goat cheese, parsley and mint.
Preheat oven to 425°F. Place a 17 x 15-inch sheet of parchment paper on a work surface and dust lightly with flour. Unwrap chilled pastry and knead the dough 3 to 4 times until it becomes pliable and holds together. Roll out dough on paper into a 10 x12-inch rectangle that is 1/8 inch thick. Cut dough into 4 sections, approximately 4 x 6 inches each.
Mist a baking sheet with cooking spray. Place chicken on baking sheet and top each with 1/4 cup mushroom mixture. Top with cheese mixture, dividing evenly. Drape pastry sections over each chicken breast, but don't tuck under. (TIP: Do not enclose chicken completely in pastry, as that would cause chicken to steam and pastry to become soggy.) Bake for 20 to 25 minutes, until chicken reaches 165°F.