Make the crust: Whisk together oat flour and cocoa powder (sift the cocoa powder first since it tends to clump). Stir in peanut butter and maple syrup until the mixture starts to clump, then add melted coconut oil and mix until evenly moistened and big clumps form. Tip: The dough should hold together when you press it between your fingers. If it's still too dry, add a bit more melted coconut oil or maple syrup.
Press crust into pan: Transfer the crust mixture to your lined pan. Press the mix into the bottom and up the sides of the pan. It won't cover all the way up the sides but cover as much as you can. The crust may feel a little crumbly but should just stick if you press it together. Freeze for up to 20 minutes while you prep the filling. If you're making the filling later, put the crust in the fridge.
Make filling: Add all filling ingredients to a blender and blend until smooth and fluffy. Taste and add extra sugar if desired. Pour the filling into the crust and smooth out the top. Refrigerate for at least 1 hour to firm up more.
Make ganache: Add chocolate chips and soy milk to a small microwave-safe cup. Heat in the microwave for 20-30 seconds until soy milk is hot and chocolate chips are starting to melt. Be careful not to overheat it or the chocolate will burn. Slowly whisk together until a thick, smooth ganache forms. Spread the ganache onto the chilled peanut butter filling. The ganache will start to set once it touches the cold filling, so work quickly.
Chill: Place the pie into the fridge uncovered to chill for at least 1 hour, but the texture is best after resting overnight. Cover the pie the next day and consume within 3 days for best flavor.
Notes
1) To make this gluten-free, be sure to use gluten-free oats*. While oats themselves are naturally gluten-free, they can be contaminated with gluten during processing.