I've made this pie more times than I remember in countless different variations of ingredients and I've achieved perfection.
Step 1: Gather your ingredients for your double crust.
3 cups of flour
2 sticks of butter chopped into cubes (super cold, but not frozen)
1 tbsp sugar
1 tsp salt
Step 2: Prepare your food processor.
Add your dry ingredients to your food processor and pulse a few times. Start adding your butter approximately 1/4 at a time pulsing in between 1/4's.
Step 3: Add cold water.
Add 1/2 cup of cold water approximately 1/3 at a time pulsing in between 1/3's. You should be able to pinch your dough between your fingers and it will stick.
Step 4: Form your dough.
Empty your food processor into a bowl and press your dough into 2 rounds. DO NOT KNEAD. If you knead your dough it will melt the butter and you need that butter intact to make your dough crispy. Also try to minimize the amount of time you are handling your dough. Your own body heat and friction will melt the butter. Use your strength and just press the dough together into a round. Refrigerate for at least an hour before rolling it out.
Step 5: Gather your fruit & prepare your mangoes.
I'm using a dozen granny smith apples and about 8 oz dried mangoes. Start by tearing or cutting your dried mangoes into smaller pieces. It's up to you how small.
Step 6: Mix your dry ingredients.
3/4 -1 cup brown sugar
A little less than 1/4 tsp nutmeg
1 tsp cinnamon
pinch of salt (optional)
Step 7: Peel & Slice your apples.
Grab your apples then peel, slice, and core them. As your peel your apples soak them in water to keep them from browning. Do the same as you slice them.
Step 8: Strain your apple slices.
Strain the water and get ready to make your pie filling.
Step 9: Gather all your ingredients for you pie filling.
Start by adding your dry ingredients to your apples and toss. Add your dry mango pieces second and toss. Finally add your lemon zest and lemon juice and give it one final good tossing so everything is mixed together well.
Step 10: Add cornstarch to your pie filling.
I add the cornstarch last so I can gauge how much to use based on liquidity of the filling. In most cases you'll need 3-4 tbsp.