Heat oven to 325F. Grease and flour pan. In medium saucepan, over low heat, melt the butter and chocolate chips together. Stir until smooth. Remove from heat and pour into a medium bowl. Add sugar and cocoa. Stir until blended. Add eggs, one at a time, mixing well after each addition. Add flour and salt. Mix until blended. Spoon batter into bottom half of pan (without holes) filling each well so it mounds over the top of the pan. I used a medium scoop for this—so easy!
Place top half of pan on top and secure with keys. Bake for 20-25 minutes, until toothpick inserted comes out almost clean. Cool 5 minutes in pan, then remove cake pops from pan to cool completely.
Melt white chocolate or chocolate bark according to package directions. Dip cake ball in melted chocolate. Dip cake pop in melted chocolate, spinning to let excess chocolate drip off. Decorate with sprinkles as desired. Repeat with all balls. Place on cooling rack or parchment paper to set.