The placing of one's fist into one's grundle and letting it bake there for a minute, then removing it and punching another person across the face with it.
Bitch, if you don't shut your mouth, you're gonna get a big ol' grundlemuffin!
by Head Chef McC December 20, 2006
1 more definition
A delicious mix of excavated nuts, mixed with grundle juice (see prior reference)and nether-yeast, baked overnight after a 5 hour tequila fu*k. Serve warm with coffee.
Honey, bring me some grundle muffin and some aspirin.
by Viva La Grundle January 24, 2006