Special equipment: 30 to 40 (6-inch) candy/lollipop sticks.
Melt the chocolate in a heatproof bowl over simmering water. Dip 1 candy/lollipop stick into the melted chocolate (this will help the brownie adhere better to the stick). With clean hands, or wearing rubber gloves, scoop out 1 heaping tablespoon of brownie. Mold the brownie onto the stick, making sure the brownie is somewhat secure. Carefully dip/paint each stick individually with melted chocolate with the help of a spoon, allowing some of the chocolate to get onto the stick. This will act as glue and keep the pop from falling apart when you bite into it. Dip into different toppings, as desired. Place onto a parchment-lined baking sheet.
Once all the pops are finished, place into the refrigerator for about 30 minutes to set.
Preheat your oven to 325 degrees F.
For your brownie batter, melt your butter in a medium (or large) heatproof bowl over a pot of simmering water.
While the butter is melting, whisk the cocoa powder, sea salt and sugar in a separate bowl. (The sugar and salt will work as abrasive agents to get any lumps out of the cocoa.) Whisk the cocoa/sugar/salt combo into the melted butter until the sugar has dissolved fully. The mixture should look like fudge and pull away from the bowl into a ball. Take off the stove and set the pan on a dishtowel on your counter. Allow the fudgy mixture to cool down until it's warm, but not hot anymore.
While that is cooling, line the bottom and sides of your 9 by 13-inch baking pan with parchment paper or foil. You want to leave about 4 inches of overhang on the 2 opposite sides. These serve as your handles to remove the brownies from the pan in 1 piece, so make sure that there is enough of the overhang for you to have a solid grip. Grease the parchment or foil well.
Stir in the vanilla into the cooled fudge mixture to loosen it up. Add the eggs into the mixture 1 at a time, adding the second egg after the first egg is fully incorporated. The batter should look shiny and well blended. Add in your flour and stir it until it's fully incorporated. Once it looks fully blended, beat the batter vigorously for at least 45 strokes. This'll not only get out any pent up stress, but it will make the brownies chewy. Fold in your chocolate chips. Spread the very thick and fudgy brownie batter evenly in the lined pan with an offset spatula or your greased hands.
Pop the brownies in the oven and bake until they get a nice crust and your house smells like brownies, 20 to 25 minutes. Let them cool completely on a rack or a dishtowel on your counter.
Try to get someone to help dip the brownies into the chocolate while you are molding. The heat from your hands helps the brownies stick better to the pop and is better to dip quickly, rather than the brownie drying out and falling apart in the chocolate.