Preheat the oven to 350℉ and prep your 24-cup mini muffin pan by greasing it with melted butter or spraying it with a baking spray.
In a medium sauce pan over medium heat, melt the butter completely, then remove it from the heat and add in neutral oil, granulated sugar, brown sugar, dutch process cocoa powder, and dark chocolate.
Return the sauce pan to the heat and stir until there are no clumps, and the chocolate has melted.
Remove the pot from the heat and let sit for 5-7 minutes for the mixture to cool.
Once cooled, add the eggs and whisk vigorously for 1-2 minutes until it's smooth and glossy.
Lastly, add flour and salt, and fold in using a spatula until just combined.
Using a cookie scoop or a measuring spoon, pour batter into each muffin well, about ¾ to ⅔ full.
Bake for 13-15 minutes until the brownie bites have risen and the tops are glossy and crinkly.
Remove from the oven and let cool for at least 15 minutes before removing from the pan.
