Make Chocolate Cake: Preheat oven to 350 degrees F. Grease and flour a 9-inch round baking pan.
In a mixing bowl, whisk together the sugar, flour, cocoa powder, baking powder, baking soda, and salt. Add the eggs, milk, oil, and vanilla, and beat on medium speed for 2 minutes. Using a rubber spatula, gently stir in the boiling water (the batter will be thin). Pour into the prepared pan.
Bake until a toothpick inserted in the center comes out with moist crumbs attached, about 30 minutes. Cool in the pan for 10 minutes, the remove to a wire rack to cool completely.
Make the Chocolate Frosting: Place the chopped chocolate in a microwave-safe bowl and microwave in 30-second increments on 50% power, stirring after each, until the chocolate is melted and smooth. Set aside to cool to room temperature.
Meanwhile, using an electric mixer, beat the butter on medium-high speed for 5 minutes, stopping to scrape the bowl once or twice.
Reduce the speed to medium-low and gradually add the powdered sugar. Once all of the powdered sugar is incorporated, add the vanilla, mixing until incorporated. Add the melted chocolate and whip at medium-high speed until light and fluffy, about 2 minutes, scraping the bowl as needed to incorporate all of the chocolate.
Make the Vanilla Cake: Preheat oven to 350 degrees F. Grease and flour a 9-inch round baking pan.
In a medium bowl, whisk together the flour, baking powder, and salt.
Using an electric mixer, cream together the butter, vegetable oil, and sugar until creamy and well-combined, 2 to 3 minutes.
Add the eggs, one at a time, beating well after each addition and scraping the sides of the bowl as needed. Beat in the vanilla extract until combined.
Using a rubber spatula, alternate adding the flour mixture and the buttermilk, starting and ending with the flour mixture, and mixing until just combined.
Transfer the batter to the prepared pan and smooth into an even layer. Bake until a toothpick inserted into the center comes out clean, 25 to 30 minutes. Cool the cake in the pan for 10 minutes, then remove to a wire rack to cool completely.
Make the Vanilla Frosting: Using an electric mixer, beat the butter on medium-high speed for 5 minutes, stopping to scrape the bowl once or twice.
Reduce the speed to medium-low and gradually add the powdered sugar. Once all of the powdered sugar is incorporated, add the vanilla, mixing until incorporated. Add the heavy cream and whip at medium-high speed until light and fluffy, about 2 minutes, scraping the bowl as needed.
Assemble the Cake Pops
Crumble the cooled cake into a large bowl, leaving no large chunks of cake. Add the frosting to the bowl and, using a rubber spatula, fold and stir in the frosting until it has evenly coated all of the cake crumbs.
Use a small cookie scoop (or 1 tablespoon) to scoop out the cake mixture and roll into a ball; place on a lined baking sheet. Cover with plastic wrap and refrigerate until firm, 2 to 3 hours. At this point, you can smooth out the balls, if you’d like. If you do so, return them to the refrigerator for at least 30 minutes.
Melt the coating in a tall cup (a 2-cup measuring cup or mason jar works well for this!). If using melting wafers, follow the melting instructions on the package. If using chocolate, combine the chocolate and vegetable shortening and microwave on 50% power, stirring every 30 seconds, until completely melted and smooth.
Work with only a few cake balls at a time and leave the remainder in the refrigerator. Dip a lollipop stick about ½ inch into the melted coating, then insert about halfway into a cake ball. Dip the cake ball the entire way into the melted coating, ensuring that the coating meets the coating on the lollipop stick, which will secure the cake pop. Allow excess coating to drip off (at this point you can decorate with sprinkles, if desired), then insert the cake pop upright in a styrofoam block. Allow to set completely (about 1 hour at room temperature) before removing.
Cake pops should be stored in the refrigerator in an airtight container for up to 1 week. Finished cake pops can also be frozen in an airtight container for up to 2 months.
Semi-Homemade Option: If you want to save time and/or ingredients, you can use a box cake mix and canned frosting. Just follow the same directions for assembly!
Mix-Ins and Toppings: See the post above for tons of mix-ins and topping ideas.
Combo Ideas: See above for how to make the following - Cookies and Cream, Peanut Butter Cup, Lemon Pops, Red Velvet, and Funfetti.
Storing: Keep cake pops in an airtight container in the refrigerator for up to 1 week.
Freezing: Finished cake pops can also be frozen in an airtight container for up to 2 months.
Making Ahead: I like to make the cake and frosting the night before I plan to assemble cake pops to save on time. Alternatively, you can make your cake pops up to 2 months in advance and simply store them in the freezer.