Preparation

做蛋糕

• Position a rack in the middle of the oven and heat the oven to 350°F. In a double boiler, melt the chocolate with the warm water. Let cool to room temperature.

  将18×13英寸的有框烤盘（标准的半平底锅）和软黄油涂上润滑。将锅中的羊皮纸排成；黄油，然后面粉羊皮纸。

  使用电动搅拌机，将蛋黄以中高速的大碗将其鞭打，直到颜色发光并开始变稠，在站立式搅拌机中2至3分钟，或者用手动搅拌机使用3至5分钟。加入1/2杯糖，然后鞭打直到非常厚和浅黄色，约2分钟。将速度降低至低，并混合融化的巧克力。用橡胶刮刀搅拌，加入可可和盐混合。

  In a clean, dry bowl with clean, dry beaters (any grease will keep the whites from whipping), whip the egg whites with an electric mixer at medium speed until they’re frothy and begin to increase in volume, about 30 seconds. In a steady stream, add the remaining 1/2 cup sugar. Increase the speed to medium high and whip until soft peaks form, 2 to 3 minutes in a stand mixer, or 4 to 6 minutes with a hand mixer.

  With a rubber spatula, fold the whites into the chocolate mixture in two equal additions. You can fold in the first half vigorously to lighten the yolks, but fold in the second half gently, mixing just until the batter is evenly colored with no streaks of white. Don’t overmix. Scrape the batter into the baking pan, gently spreading and smoothing it to make sure it’s level. Bake until the top springs back lightly when touched, 22 to 25 minutes.

  同时，在柜台上撒上干净的洗碗奶油（至少与蛋糕盘一样大）。用筛子用可可粉将毛巾粉到毛巾上，完全覆盖它（这会防止蛋糕在冷却时粘在毛巾上）。

滚蛋糕，让它冷却：

• Immediately after taking the cake from the oven, run a small knife around the inside edge to loosen it from the pan. Invert the cake pan onto the towel in one quick motion. Remove the pan. Carefully peel off the parchment. Using both hands and starting from one of the short ends, roll up the cake and the towel together. Let cool to room temperature.

做填充

• 用1到2英寸的非常热的水填充宽锅或直底煎锅。在电动搅拌机的碗中，搅拌蛋清，1/2杯糖和大量的盐，直到混合。将碗放在热水锅中；确保水至少达到碗中的混合物水平。搅拌直至混合物几乎变热（约120°F），约90秒。从水中取出碗。用中高速的电动搅拌机将白色搅打至冷且浓稠，2至3分钟。降低到中等速度，加入黄油，1汤匙。一次，混合直到黄油完全合并。馅料应柔软而宽松； it will firm up as it chills. (If it seems very runny, refrigerate it for up to 20 minutes.) With the mixer on low speed, blend in the vanilla bean seeds, vanilla extract, and orange zest.

Fill and roll the roulade:

• 小心地展开冷却的毛巾包裹的蛋糕。将馅料铺在蛋糕上，将其均匀地覆盖到边缘2英寸以内。重新滚动蛋糕，这次没有毛巾。填充物可能会稍微挤出一点。这可以。用箔纸在有边缘的烤盘上衬上，并在箔纸上放一个线架。将两个大金属铲子（或一个刮刀和您的手）滑到roulade下，然后将其转移到架子上。（或者，如果向前工作，将其转移到一大片塑料上，将其贴合，然后冷藏至一天；在玻璃上转移到架子上。）

Glaze the roulade

• 用一个大平底锅,把奶油、糖、1/2cup of the water, and the cocoa. Bring the mixture to a boil and then reduce the heat to a simmer, whisking often, until very thick, like hot fudge sauce, 8 to 10 minutes from when the mixture began simmering. Pay close attention: This mixture boils over easily. Remove the pan from the heat. While the mixture is cooling, bloom the gelatin in the remaining 1-1/2 Tbs. of water. Melt the bloomed gelatin over very hot water or in the microwave. Whisk the gelatin into the chocolate mixture and strain the glaze through a medium sieve into a metal bowl. Let the glaze cool at room temperature until thick but still pourable, about 5 to 10 minutes; the glaze should be about 110° to 120°F. (If you’ve made the cake ahead, unwrap it and put it on a rack set over a foil-lined baking sheet.)

  Pour the glaze over the roulade, using an offset spatula to help the glaze cover the top and sides evenly. Don’t worry about covering the ends; they’ll be trimmed later. Refrigerate uncovered for at least 30 minutes or up to 4 hours.

Serve the roulade:

• 釉将“将”烤面包“粘在架子上”，因此将其在架子和架子之间滑动以释放它。将roulade转移到服务盘中，使用两个大的偏移式Spatulas在下面，然后将铲子压在架子上。修剪烤龙的末端。用热水填充一个高大的容器，并用力携带洗碗剂，以便在切割每片后可以清洁并干燥刀。使用一把长而锋利的刀，切成3/4英寸的直片，或者在每切片后冲洗并干燥刀。用鲜奶油和蜜饯的橙皮和食用。

Make Ahead Tips

You can make the cake and filling and assemble the roulade (without the glaze) a day ahead. Wrap the unglazed roulade with plastic, refrigerate it, and glaze it the next day. You can prepare the garnishes ahead, too, but whip the cream close to serving time.