Mix together butter and cream cheese until well combined. Set aside.
In a skillet over medium heat, sauté onion, celery, mushrooms and garlic in olive oil and butter until soft and translucent. Add salt, pepper, paprika and red pepper flakes. Set aside to cool.
Roll out crescent dough, making the 8 triangles into 4 rectangles by firmly pressing
perforations to seal. (If you unroll dough carefully, the rectangles will already be made.) Gently stretch dough to make the rectangle slightly larger.
In a bowl, combine butter and cream cheese mixture, diced chicken and sautéed onion mixture. Spoon 1/3 to 1/2 cup of chicken mixture in center of each rectangle. Pull four corners to top center and pinch and twist to seal. (Unused dough can be used for patching if necessary.)
Bake on ungreased baking sheet at 350 degrees for approximately 20 minutes or until deep golden brown. (Cover with foil if dough gets too brown.) Remove and brush top and sides with melted butter. Makes 4-6 pockets.