Step 10:

Pour your custard into a wide pan and put it in the fridge to chill. This would also be the time to add vanilla extract if you need/want to.
  
 
 Step 11:

This gives us time to prepare the chunky bits. Pour some (how many is really up to taste) roasted edamame into a plastic bag and put it on something non-fragile.

Terminate with moderate prejudice. Don't go hog-wild with the beat stick, because doing so will result in teeny tiny bits of nut instead of nice-sized chunks. Just crush, don't maim, kill, or destroy.