Preheat oven to 325F. Grease and line an 8-inch square baking pan with overhanging parchment paper.
In a medium-sized bowl, sift together the almond flour, cocoa and salt.
In a microwave-safe bowl, add the chocolate chips and oil. Microwave on two 30-second intervals, stirring in between and after, until smooth. Let cool for 5 minutes.
Add the eggs, sugar and vanilla to a large bowl and use an electric mixer to beat on high for 3 minutes. The mixture will be thick and pale, but not quite at the ribbon stage.
Add the slightly cooled melted chocolate mixture to the egg mixture and beat until combined.
Add the dry ingredients to the wet mixture. Switch to a spatula and stir until the dry ingredients are just mixed in. Don't overmix.
Spread the batter out into the prepared baking pan. Bake for 25-28 minutes, or until a toothpick comes out with some wet crumbs on it. (It's better to underbake, than overbake brownies).
Let cool for 15-20 minutes in the pan. Then, use the edges of the parchment paper to lift the brownies out of the pan and transfer to a wire rack to cool completely.
Once cooled, cut into squares and store in a sealed container at room temperature.
Notes
Beat eggs and sugar until thick and pale. This will take some patience. I usually set a timer for 3 minutes. In that time, the mixture will thicker, but you'll want to stop before it hits the ribbon stage.
Sift dry ingredients together. I usually just whisk together dry ingredients for recipes, but when using cocoa, I like to sift it together with the other ingredients to eliminate any lumps.
Let the melted chocolate mixture cool. It doesn't need to cool completely, but leaving it for 5-10 minutes while you pull together the other ingredients will ensure the hot chocolate mixture doesn't cook the egg mixture.
Don't overmix. This is very important. Over mixed brownie batter may cause the brownies to sink in the middle. Once you add the dry ingredients to the wet mixture, put the electric mixer aside and switch to a spatula.