Pour 2 cups heavy whipping cream into a large mixing bowl and beat on medium-high speed for 2 to 3 minutes until soft peaks form.

Add 3 tablespoons powdered sugar and 1 teaspoon vanilla extract to the whipped cream and beat for 30 seconds until stiff peaks form.

In a separate bowl, whisk together 2 packages of instant chocolate pudding mix with 3 cups cold milk for 2 minutes until the mixture thickens.

Place 30 Oreo cookies into a food processor and pulse until finely crumbed, about 1 minute; alternatively, crush in a sealed bag with a rolling pin for 2 to 3 minutes.

Layer the dessert in clear glass cups by adding a quarter-inch of crushed Oreos, followed by a spoonful of chocolate pudding and a spoonful of whipped cream; repeat until cups are three-quarters full.

Spread a final pudding layer about one-quarter inch thick, then top with a smooth layer of whipped cream.

Sprinkle a generous handful of crushed Oreos on top, poke gummy worms into the surface, and dust with 2 tablespoons cocoa powder if desired.

Refrigerate the assembled cups for at least 30 minutes before serving and garnish with fresh mint leaves if using.