Preheat your oven to 330 degrees and prepare an 8×8 square baking dish (very lightly buttered and parchment lined baking dish).
In a bowl, melt your butter and dark chocolate together. I do think in a microwave safe bowl in increments of no more than 12 seconds at a time. The goal is to get both butter and chocolate melted without heating it up too much. Mix the butter and chocolate together well until they come together and set aside until it is just barely warm.
In a bowl add all your dry ingredients, flour, salt, cocoa powder and mix well. Sift your flour and cocoa powder before adding to your bowl.
In a separate bowl beat together your eggs, sugar and vanilla until light in colour. use a hand mixer for best results and mix for at least 4 minutes.
Add your cooled chocolate mixture to your eggs mixture and fold it in with a spatula until well combined.
Add your dry ingredients to the wet ingredients, folding in until well combined.
Pour mixture into a buttered and parchment lined baking dish.
Bake for 32 to 35 minutes until a toothpick comes out with moist crumbs in the centre. It should not be dry and some moist crumbs are okay. It should not be entirely covered in liquid batter though. Adjust making temp as necessary. I have had to bake it for an extra minute in the past.
Remove from the oven and let cool completely .
