In a medium bowl, combine the flour, cocoa powder and 0 calorie sweetener.
Add in the yogurt and vanilla and whisk to combine. Add in the chocolate chips and use a rubber spatula to fold them in.
Transfer the batter to a microwave safe dish, (I used a 9cm ramekin lined with parchment paper) and cook in the microwave for 1-2 minutes depending on your microwave. For reference, I used a 700W microwave and it took 2 minutes and 30 seconds. You can also use a toothpick to see when your brownie is done. After the first minutes, insert the toothpick into the center and if it doesn't come out clean with a few crumbs, microwave for another 30 seconds and check again. Repeat until the brownie is done.
Allow the brownie to cool slightly before enjoying!
Video
Notes
*To make this recipe gluten-free, use gluten-free or oat flour.