No need to make a paste first.
I take my copper pot upside-down and pour a little heap of table salt in the center of it and then wet the salt with a bit of vinegar before spreading this mix with my finger-tips over the whole outside surface of my pot .Rinse well with water and you are done
Pre-cooking your frozen apples with starch ,sugar. and butter (and raisins if you wish )is the only sure way to a great pie.
.Let the filling cool to room temperature before adding it into the pie crust.