If you have trouble finding the Praline liqueur, I suggest substituting an almond or pecan-flavored liqueur. For skillet pies like this, I've found that packaged piecrusts tend to be too small, so I double them up and roll them out for a crustier pie dough. Watch carefully that the outer crust doesn’t burn before your pie is done, and be sure to test the center with a wooden skewer to make sure the filling is set. Plan ahead: A couple of key steps are to refrigerate the streusel topping before adding to the top of the pie so that the butter chills, and to refrigerate the pie for at least 4 hours after baking so that it sets and can be sliced. I serve this either refrigerated or at room temperature with a dollop of whipped cream. And if you like, feel free to drizzle a shot of praline liqueur on top.