If using the cake filling, prepare your cake mix according to package directions. Let it cool completely.
Carefully trim 1-2 inches off the pointed tips of the sugar cones using a sharp knife. You want the opening large enough for 3 pretzel sticks but not so big they fall through.
Melt chocolate chips in 30-second microwave intervals, stirring between each, until smooth. Let cool 5 minutes.
Dip the top inch of each cone in chocolate, shake off excess, then coat with sprinkles.
Flip and repeat the process with the bottom of the cone.
Insert 3 chocolate-dipped pretzel sticks into each cone top.
For filled versions, mix cooled crumbled cake with frosting and carefully fill cones.
Notes
Let the melted chocolate cool for 5 minutes before dipping to ensure better coating
Work in small batches when dipping the cones to prevent the chocolate from hardening
Support the pretzel sticks while filling with cake to prevent them from falling out
Don't cut too much off the cone tips - you want the pretzels to fit snugly
Shake off excess chocolate gently to prevent drips and ensure even coating