Preheat your oven to 230 C.
To make the topping, combine all of the topping ingredients in a bowl and use a fork to mix completely, set aside.
To make the filling, peal, core and slice the apples to about 1/8 inch slices then toss the slices with the sugar, cinnamon, nutmeg, and flour. Layer the slices into the unbaked pie crust, it will be full and heaping, any leftover juices from the apples, pour that over the apple slices as well. Now pile on the topping and pat it down a bit over the apples.
Set the pie dish on a cookie sheet in case of overflows, and bake for 15 minutes, then reduce the temp to 180 C and continue to bake for another 45 minutes. If the topping is browning too much, place a sheet of foil over the top. Run a butter knife through the center at the 45 minute mark, it should insert easily indicating all the apples are cooked through. Removed from the oven and serve warm or room temp. Ice cream or whipped cream on top would be a nice touch.