Preheat oven to 350F and prepare an 8×8 baking pan by lining it with parchment paper leaving a few inches of overhang on the sides to allow for easy removal. Grease the parchment and set aside.
Melt coconut oil and baking chocolate in a small saucepan set over low heat.
Stir until oil and chocolate have melted before removing from heat and setting aside to cool slightly.
Using a handheld mixer with a whisk attachment, beat together eggs, sugar, and vanilla extract until smooth and pale, about 2 minutes.
Add melted chocolate mixture and mix until well combined.
Reduce speed to low and add cocoa powder, corn starch, and salt. Mix until well combined. Batter should be thick and smooth.
Pour batter into prepared pan, spreading it evenly with a greased spatula.
Bake for 25-30 minutes, until center is set.
Remove from oven and let cool in pan for 15 minutes.
Cut into squares and serve warm.