Preheat oven to 350°F. Line 13×9-inch baking pan with foil, with ends of foil extending over sides of pan. Grease foil.
Microwave chocolate and butter in large microwaveable bowl on HIGH 2 min. or until butter is melted. Stir until chocolate is completely melted. Stir in sugar. Blend in eggs and vanilla. Add flour and salt; mix well. Spread into prepared pan.
Bake 30 to 35 minute or until toothpick inserted in center comes out with fudgy crumbs. (Do not overbake.) Cool in pan on wire rack. Remove brownies from pan, using foil handles.
Cool brownies, then cut* them into 3/4- to 1-inch squares for use in the cheesecake. You will have more than the two cups of cubes, loosely measured, than you will need, and I’m sorry, you’re just going to have to decide for yourself what to do with the extra. Add cubes to cake batter as directed below.
* I find that brownies are fantastically easy to cut once they’ve been refrigerated–you end up with nice clean lines, and in this case, a sharp pizza wheel was especially helpful. Also, brownies taste better cold. I’m just saying.
I like a doubled crumb crust. I can’t get enough cookie. Below are proportions for one crust with the amounts to double the recipe in parentheses. You know you wanna.
Stir together crust ingredients and press onto bottom and 1 inch up side of a buttered 24-centimeter springform pan. Fill right away or chill up to 2 hours.
Make crumb crust as directed above for 24-centimeter cheesecake. Preheat oven to 350°F.
Make filling and bake cake: Beat cream cheese with an electric mixer until fluffy and add eggs, 1 at a time, then vanilla and sugar, beating on low speed until each ingredient is incorporated and scraping down bowl between additions.
Fold brownie cubes in very gently and pour mixture into prepared pan. Put springform pan with crust in a shallow baking pan. Pour filling into crust and bake in baking pan (to catch drips) in middle of oven 45 minutes, or until cake is set 3 inches from edge but center is still slightly wobbly when pan is gently shaken.
When completely cool, top with following glaze.
Grind the chocolate into powder in the food processor, scald the butter and cream in a saucepan (or in a Pyrex cup in the microwave). With the machine running, pour the hot cream/butter mixture slowly through the feed tube onto the chocolate. Blend until completely smooth, stopping machine to scrape down sides once or twice. Add the extract and sugar and process until smooth. Spread over cheesecake while ganache is still warm. Chill until ready to serve.