Preheat oven to 350°F (175°C). Grease your pie dish or line with parchment.
Mix dry ingredients
In a bowl, whisk together flour, cocoa powder, and salt. Set aside.
Combine wet ingredients
In a large bowl, whisk melted butter with both sugars until smooth.
Add eggs & vanilla
Add eggs one at a time, mixing well after each. Stir in vanilla extract.
Combine wet + dry
Gradually fold dry ingredients into wet mixture. Do not overmix.
Add chocolate chips
Fold in chocolate chips or chunks evenly.
Pour into pan
Spread batter evenly into prepared pie dish.
Bake
Bake for 30–35 minutes.
Edges should be set
Center should still look slightly soft for gooey texture
Cool slightly
Let sit for 10–15 minutes before slicing.