at what temperature should apple-choco pie be prepared? I have done this in the past but didn't really get the pie to turn out like I expect. I am wondering if I am not cooking it at the correct temperature since all the other aspects of the apple-choco pie recipe have been followed.

Here is the recipe:
ingredients


  For the chocolate pastry:
  3/4 cup plain wheat flour (maida)
  3 tbsp cocoa powder
  5 tbsp powdered sugar
  4 tbsp butter/ghee
  
  For the filling:
  2 apples chopped in small pieces
  2 tbsp brown sugar
  2 tbsp chopped nuts (walnut, cashew)
  
  Make the pastry: 
  mix all the ingredients in a bowl and add the butter into the flour, till it resembles bread crumbs. Add 1 tablespoon of cold water to gently knead it into a firm dough. Refrigerate for 15 minutes. Roll out 2/3 of the dough into a circle. Prick with fork at regular intervals and refrigerate for 10 minutes. Bake it in a pre-heated oven at 300°F for 15 minutes.
  
  Make the filling: 
  mix the apple(chopped), sugar, walnuts &amp; keep aside.
  
  Place the filling on the half baked chocolate pastry and sprinkle the sugar mixture on top. Cover with the remaining rolled out chocolate pastry and seal the edges.  Prick the top of the pie with a fork at regular intervals. Bake in a pre-heated oven at 300°F until
  golden brown.


But it still didn't have the taste I wanted. In fact, it wasn't baked properly. What mistakes were there that resulted in the base of the pie being sticky?

What other fruit can I use instead of apples, other than dry fruits? Which tastes better than apples?
The pre-baking of the pastry is missing a "how to tell when it's done" instruction. My guess is there's a good chance you didn't bake it long enough. In general, when pre-baking plain pie crusts, you're aiming for golden brown. It's a bit harder to tell when it's got the brown from the chocolate in it, but if you look closely you should still be able to see the change in color. It should also just look cooked - a bit of texture develops on the surface and it appears to have dried out. As SAJ14SAJ suggests, you also normally pre-bake crusts with weights in them to keep them from bubbling too much. (This is also why you poke holes.) A common method is to cover with a piece of foil, then fill with dry beans.

As for temperature, in my experience, pie crusts are generally pre-baked at 350°F. But the important thing is to check and know when it's done.

Now, baking the filled pie. This is the weird thing - usually apple pies don't use pre-baked crusts, because it takes more like an hour to fully cook the apples til they're soft. Maybe you didn't like the apples because they were still crunchy and a bit raw, and the flavor hadn't smoothed out with the nuts and sugar? If that's the case, you may want to skip pre-baking the crust, and instead fill and cover the pie and bake it all together, for 45 minutes to an hour. If the crust browns too much, you can loosely cover it with foil.

If on the other hand, you like the apples like that, or the quantity of apples is sufficiently small that they're actually cooking fully, then sure, stick to the recipe. (You could increase the temperature to 350°F here too, but that'll mean the crust is done when the apples are even less done.) If you've properly pre-baked the crust, you shouldn't have problems with the bottom of the pie being undercooked.