vegetable oil spray
1-ounce unsweetened chocolate
3 tbsp Dutch-processed cocoa powder
1/3 cup water
5 tbsp vegetable oil
2 tbsp unsalted butter (melted and cooled)
1 1/4 cup sugar
1 large egg
1 large egg yolk
1 tsp vanilla extract
3/4 cup + 2 tbsp all-purpose flour
1/2 cup bittersweet chocolate chips
1/2 tsp salt
8-inch square metal baking pan
large zipper-lock plastic bag
liquid measuring cup
Adjust oven rack to lowest position and preheat oven to 350F. Make an aluminum foil sling for a square cake pan and spray with vegetable spray.
Place the unsweetened chocolate into a Ziplock bag, remove as much air as possible. Gently pound the chocolate into smaller pieces with a rolling pin. Place the chocolate in a large bowl with the cocoa.
Heat the water until hot and add to the chocolate mixture, whisk until smooth.
Add oil, melted butter, sugar, egg, egg yolk and vanilla and whisk until smooth. Add flour, chocolate chips and salt and combine with a rubber spatula until no flour is visible. Scrape batter into prepared pan and bake for 25-28 minutes, until few moist crumbs attach to a toothpick inserted in the center. Allow to cool completely in the pan before using the foil sling to carefully lift from the pan.