Preheat the oven to 350ºF and line an 8-inch square pan with parchment paper. (I like to spray the pan lightly with oil first, so that the parchment paper will stick in place.)
In a large bowl, combine the almond flour, coconut sugar, cacao, eggs, oil, baking soda, vanilla, and salt, and stir well to form a thick batter. It will be much thicker and stickier than a traditional brownie batter, so be sure to mix well and break up any lumps.
If adding the mini chocolate chips, reserve 2 tablespoons to sprinkle over the top, then fold the rest of them into the batter. Transfer the batter to the prepared 8-inch pan, then use a spatula (or use wet hands) to press the batter evenly into the bottom of the pan. It's okay if it's not perfectly smooth, because the batter will spread and expand as it cooks. Sprinkle the reserved chocolate chips over the top.
Bake at 350ºF until the center of the pan doesn't jiggle, about 25 to 30 minutes. If using a larger 9-inch pan, the brownies might cook a little faster, so be sure to keep an eye on them around the 20 to 25 minute mark. It's normal for the brownies to puff up in the oven, and then deflate slightly as they cool.
Let the brownies cool for at least an hour before slicing them into 16 squares. They probably won't last long before they are all eaten, but I recommend storing these in an airtight container in the fridge for the best shelf life. They should last in the fridge for up to 5 days, if you don't eat them all by then.