Firstly, harvest some wheat and thresh it using a branch.
Pick up the threshed wheat using a bowl.
Use a round stone on the bowl of wheat in order to create flour.
Add a bowl of water to the bowl of flour in order to create dough.
Use the bowl of dough on a empty plate in order to make the pie crust.
This will create four pie crust.
Do not leave the dough sitting in the bowl for too long!
Each pie is 4 servings (save for the pumpkin pie which has 8 servings).
Though you should only ever eat one bite of each pie during a lifetime! Remember to always YUM!

There are currently 9 different types of pie in-game.
Here are the 8 types of pie fillings :
Only the raw berry bowl can be added to the pie crust directly. All of the other fillings must be mashed with either a flint chip, a sharp stone or a knife beforehand.
Lastly is the pumpkin pie which is a bit more complicated...
You must firstly cook the pumpkin custard filling in a crock pot before adding it to the pie crust.
To make the pumpkin custard filling just follow the directions listed below :

To make the pumpkin custard, you must have the following items :

• 1 Pumpkin
  
• 1 bowl of sugar
  
• 1 egg
  
• A crock pot
  
• Either a hatchet or an axe

Place the pumpkin on a plate and use either a hatchet or an axe to get a plate of pumpkin chunks.
Remove the 3 seeds for later use and dump the pumpkin chunks into a crock pot.
Add the bowl of sugar.
Place the crock pot onto hot coals and let cook.
Once the sugared pumpkin is finished cooking, add the egg to the mixture in order to make pumpkin custard.
1 crock pot is enough to fill 4 pie crust.

Once you have several raw pies ready, set them close to the oven in either slot boxes or in baskets.
Note the pumpkin pies can not be placed in either of these.
Once you set the oven alight you will only have 1 minute to bake everything so it's best to have everything needing cooked in the same area.