Turkey Leek Pot Pie with Sage & Walnut Studded Puff-Pastry

turkey meat, coarsely chopped

leeks, white and light green parts thinly sliced (I like to save the dark tops in the freezer for homemade stock)

rashers Applewood smoked bacon, coarsely chopped

sprigs fresh thyme, leaves picked

turkey or chicken stock

flour

crème fraîche or sour cream

Salt and pepper,

package frozen puff pastry, thawed in fridge

walnuts, coarsely chopped

fresh sage leaves

egg, lightly beaten + 1 tsp water (egg wash)