Add the sugar, cocoa powder, cornstarch, and salt to a saucepan and stir. Slowly add the milk, whisking as you pour it in.
Heat the mixture over medium heat, whisking occasionally. Once the mixture is boiling, reduce the heat to a simmer and allow to simmer for 2-3 minutes, whisking continuously until thickened.
Remove from the heat and add the butter and vanilla. Stir until the butter is melted and incorporated.
Allow the pudding to cool at room temperature for about 15 minutes. Pour into a heat-proof container. Cover and chill in the refrigerator for about 1-2 hours.
After the chill time, assemble the pudding cups. Start by adding ½ cup chocolate pudding to a glass or cup. Top with a 1-inch layer of crushed Oreos, followed by another ½ cup chocolate pudding. Place a final 1-inch layer of crushed Oreos on top of the pudding, then 3 gummy worms on the top of each cup.
Serve or chill until ready to serve!
Notes
We used 11-ounce glasses for these. You could also use 10 or 12 ounce glasses.
This recipe makes 4 cups of pudding and can easily be doubled to make more dirt and worm cups!
You can totally add more gummy worms per cup if you want to.