Instructions

Adjust oven rack to middle position and heat oven to 350 degrees. Grease 9-inch springform pan. Combine chocolate and butter in bowl and microwave at 50 percent power, stirring occasionally, until melted, 2 to 4 minutes. Let cool for 5 minutes.
Whisk 1 cup sugar, eggs, vanilla, baking powder, and salt together in medium bowl until combined, about 15 seconds. Whisk in chocolate mixture until smooth. Stir in flour until no streaks remain. Transfer batter to prepared pan and distribute evenly.
Bake until toothpick inserted in center comes out with few crumbs attached, 22 to 27 minutes, rotating pan halfway through baking. Transfer pan to wire rack and let cool completely, 2 hours.
Combine 1 teaspoon gelatin and water in small bowl and let stand until gelatin softens, about 5 minutes. Place white chocolate in large bowl. Heat Bailey’s and espresso powder in small saucepan over medium heat until just simmering. Pour Bailey’s mixture over white chocolate, add gelatin mixture, and whisk until melted; let cool slightly, about 5 minutes. Using stand mixer fitted with whisk, whip cream on medium-low speed until foamy, about 1 minute. Increase speed to high and whip until soft peaks form, 1 to 3 minutes. Whisk one-third of whipped cream into white chocolate mixture. Using spatula, fold in remaining whipped cream. Spread evenly over brownie layer in pan. Refrigerate until set, about 2 hours.
Combine orange juice, remaining 2 tablespoons sugar, Grand Marnier, and remaining 1 1/2 teaspoons gelatin in small saucepan and cook over medium-high heat, stirring frequently, until just simmering. Transfer to 2-cup liquid measuring cup and let cool completely, about 1 hour. Slowly pour juice mixture over cake and refrigerate until set, about 1 hour. Run thin knife between cake and side of pan; remove side of pan. Transfer cake to cake platter. Place chocolate curls in center of cake. Serve.