Preheat the oven to 300F. Grease a 9x5.5-inch (1.5qt) loaf pan with baking spray, line with parchment paper. Set aside

In a medium saucepan over medium-low heat, melt the chopped chocolate and butter until smooth. Set aside and allow to cool.

In a large bowl, combine the dry ingredients: flour, sifted cocoa powder, baking soda, baking powder, granulated sugar, light brown sugar and salt. Whisk until fully incorporated.

In a separate bowl, whisk the eggs. Add the remaining wet ingredients, including the cooled melted chocolate and stir until smooth.

Combine both mixtures until you have a thick and luscious batter. Fold in 1/2 cup of the chocolate chips.

Transfer batter to loaf pan and smooth out the top using an angled spatula. This batter works perfectly in a 9x5.5 inch pan. If you're using a different size, make sure you don't fill the pan all the way to the top (leaving at least 1 inch from edge), so you can avoid overflow.

Bake for 55-62 minutes, or until a toothpick inserted in the center comes out mostly clean (avoid using a knife). This is a fudgy and moist batter so it won't come out clean, but it shouldn't be too wet.

Remove from oven and immediately sprinkle the remaining 1/2 cup of chocolate chips on top.

Cool for 10 minutes and transfer to a cooling rack. Enjoy while warm!