Ingredients
1 cup semisweet chocolate chips
1 1/2 sticks (6 ounces) unsalted butter, cut into pieces
4 ounces unsweetened chocolate, chopped
1 1/2 cups granulated sugar
3 large eggs, plus 1 egg yolk
1 teaspoon vanilla extract
3/4 cup all-purpose flour
1/2 teaspoon salt
Preparation
