Prepare the brownie mix according to the package instructions in an 8x8-inch pan. Bake at 350°F for about 25–30 minutes. Let cool completely.

In a large bowl, combine the instant vanilla pudding mix with 2 cups of cold milk, whisking for about 2 minutes until thickened. Add a few drops of green food coloring.

Crush the mint Oreos in a Ziploc bag using a rolling pin until they resemble coarse sand.

Layer the trifle in a bowl or cups starting with brownie pieces, followed by pudding, Cool Whip, and crushed Oreos. Repeat layers until done.

Cover the trifle with plastic wrap and refrigerate for at least 2 hours.

Serve cold, showcasing the beautiful layers.