Preheat the oven to 350°F. Line an 11x17” baking pan with parchment paper.
In a small saucepan over low heat or in a microwave-safe bowl, place the 1/3 cup of chocolate chips, water, and sugar. Microwave in 15 second intervals until the chocolate chip are melted and the mixture is smooth.
In a large mixing bowl, whisk together the gfJules Flour, salt, cocoa powder, and baking powder.
Add the melted chocolate mixture, eggs, oil, and vanilla. Stir until a smooth batter forms.
Pour the batter onto the baking pan. Spread the batter out to the edges of the pan in an even layer using a rubber spatula. If using, sprinkle the ½ cup of chocolate chips over the batter.
Bake for 35 minutes for brownie brittle with crispy edges and a soft middle; bake for 40-45 minutes for brownie brittle that is crispy all the way through.
If using, sprinkle flakey sea salt over the warm brittle as soon as it comes out of the oven.
Allow the brownie brittle to cool in the pan for 4+ hours before breaking or cutting it into pieces.
Store in an airtight container at room temperature.