Passover Chocolate Cake Dessert

Make the cake: Preheat oven to 350°F. Oil a half-sheet pan and line the bottom with a large piece of wax or parchment paper, letting paper hang over ends. 2. Melt chocolate with water in a small heavy saucepan over very low heat, stirring. Cool to lukewarm. 3. Beat yolks, 1/3 cup sugar, and salt in a large bowl until thick and pale. Fold in melted chocolate until blended. 4. Beat whites until they just hold soft peaks. Gradually add remaining 1/3 cup sugar and beat until whites just hold stiff peaks. 5. Fold one third of whites into melted-chocolate mixture to lighten, then fold in remaining whites gently but thoroughly. 6. Spread batter evenly in baking pan and bake in middle of oven until puffed and top is dry to the touch, 15 to 18 minutes. Transfer pan to a rack. Cover top with 2 layers of damp paper towels and let stand 5 minutes, then remove towels and cool completely. 7. Loosen edges with a sharp knife. 8. Sift cocoa powder over top of cake layer and overlap 2 layers of wax paper lengthwise over cake. Place a baking sheet over paper and invert cake onto it, gently peeling off wax paper lining. (Don’t worry if cake layer cracks; it will hold together when you roll it.) 9. Make the filling: Beat cream with cream cheese and powdered sugar until it just holds stiff peaks. 10. Fill and roll: Spread filling evenly over cake. Put a long platter next to a long side of cake. Using wax paper as an aid, roll up cake jelly roll-style, beginning with a long side. Carefully transfer, seam side down, to platter, using wax paper to help slide cake. (Cake will crack but will still hold together.) 11. Dust cake generously with cocoa powder and powdered sugar.