Whisk the instant pudding mix and cold milk together for 2 minutes until thickened. Add orange gel food colouring a few drops at a time, whisking in, until the pudding is a deep pumpkin orange.
Refrigerate the pudding for 5 minutes to firm it up slightly.
Spoon a layer of crushed cookies into the base of each cup, about 2 tablespoons deep.
Spoon or pipe the orange pudding on top of the cookie layer, filling each cup about two-thirds full.
Refrigerate for at least 1 hour or up to 24 hours until the pudding is set.
Just before serving, scatter a second thin layer of cookie crumbs over the pudding surface to look like fresh soil.
Press three candy pumpkins into each cup, pushing them slightly into the crumbs so they stand upright. If using, tuck a short pretzel stick behind each pumpkin as a stem.