Brownies
1/2 cup all-purpose flour
1/2 teaspoon baking powder
1/8 teaspoon salt
1/4 teaspoon ground cinnamon (optional)
6 ounces high quality bittersweet chocolate*
1/2 cup unsalted butter, cut into pieces
2/3 cup granulated sugar
3/4 teaspoon pure vanilla extract
2 large eggs (at room temperature)

Position a rack one-third up from the bottom of the oven and preheat the oven to 350 degrees F. Butter a 9-inch square baking pan and set aside.

Place flour, baking powder, salt and, if desired, cinnamon in a bowl and stir with a whisk to combine; reserve. Melt chocolate and butter together in the top of a double boiler over hot water or in a bowl in the microwave. When melted, stir to blend. Add the sugar and mix well, using a small whisk (it is not necessary to pour the chocolate mixture into a bowl). Add vanilla extract and eggs, one at a time, stirring after each addition until the mixture is smooth. After the eggs are added, the chocolate may look grainy, but it will smooth as you stir it. Blend in reserved dry ingredients. Set aside while you prepare the cheesecake.

Cheesecake
1 1/2 teaspoons instant espresso powder
1 tablespoon boiling water
8 ounces cream cheese (at room temperature)
2/3 cup granulated sugar
1/2 teaspoon pure vanilla extract
2 large eggs (at room temperature)
1 tablespoon all-purpose flour

Dissolve espresso powder in boiling water. Set aside to cool. Beat cream cheese in a mixer, with a paddle if available, until it is very creamy. Add sugar and vanilla extract and beat until the sugar dissolves, about 3 minutes. Blend in the espresso. Beat in the eggs one at a time. Beat at medium speed for 1 minute. On low speed, add the flour and beat just until blended.

The brownie batter will have thickened a bit while sitting, so give it a turn with a rubber spatula. Pour three-quarters of the batter into the prepared pan, spreading it evenly with the spatula. Pour over all of the cheesecake batter; it will spread by itself. Scatter teaspoonsful of the remaining brownie batter over the cheesecake. Create a swirl pattern by dipping a table knife halfway into the batters and drawing it back and forth across the pan. Don't disturb the bottom layer and don't go across the pan more than once.

Bake for 30 to 35 minutes, until the top is lightly browned and the cake starts to pull away from the sides of the pan. Remove from the oven and cool on a rack for 10 minutes. When the brownies reach room temperature, cover and place in the refrigerator to chill. Serve cold.