Preheat the oven to 350°F or according to package directions.
STEP 2
Mix cake mix, water, and egg; pour into a pan. Bake as directed, about 28 to 37 minutes. Cool completely.
STEP 3
Whisk pudding mix with eggnog for 2 minutes; refrigerate until cake cools.
STEP 4
Whip cream until nearly stiff; add sugar and vanilla to form soft peaks.
STEP 5
Crumble half of the gingerbread cake in a trifle dish, spread half of the eggnog pudding, and then half of the whipped cream. Repeat layers and chill for 6 hours. Top with cranberries and cookie crumbs before serving.