Grease the sides and bottom of a 9-inch springform pan and line the bottom with parchment paper.
Place a double boiler on the stove and add about an inch of water to the bottom portion of it. You can also use a heat-proof bowl over a pan of water instead of a double boiler.
Add unsalted butter and chocolate chips to the top portion of the double boiler.
Heat over medium heat, stirring frequently, until the butter and chocolate are melted and smooth.
Meanwhile, combine the eggs and coconut sugar in the bowl of an electric mixer (or in a large bowl with a hand mixer).
Whisk at medium-high speed for 7-8 minutes. The mixture should be light-colored and airy.
Pour half of the melted chocolate mixture into the whisked egg mixture.
Use a rubber spatula to fold the chocolate into the egg mixture. It will have immediately sunk to the bottom of the bowl, so make sure you're scraping all the way to the bottom and lifting it.
Fold the remaining chocolate into the egg/chocolate mixture.
Pour the batter into the prepared pan.
Bake for about 35 minutes or until a toothpick inserted in the center comes out wet, not runny. You’ll know it’s done when there is just a slight wobble in the center and it’s no longer shiny on top.
Cool completely before serving, topping with any toppings you’d like. Raspberry sauce or a dusting of unsweetened cocoa powder are a few options!
Notes
Feel free to use any type of chocolate you like. If you want a really dark chocolate flavor, use bittersweet chocolate. If you prefer it less intense, use milk chocolate. We like the balance of semi-sweet.