Method

• 1.
  Arrange an oven rack in the centre position and preheat the oven to 350°F. Brush the bottom and sides of a 9-inch springform pan with oil, making sure to coat the sides all the way to the rim. Line the bottom with a silicone or parchment round and brush with more oil, then set the pan aside.
• 2.
  Fill a medium saucepan with about 1 inch of water and bring to a simmer over medium heat, then reduce the heat to maintain a gentle simmer. In a large heatproof bowl, combine the chocolate, oil, coffee, and 1 1/2 teaspoons salt and set it over the saucepan, taking care that the bottom of the bowl doesn’t touch the water (this is called a double boiler). Stir occasionally with a heatproof flexible spatula until the chocolate is melted and the mixture is completely smooth, then remove the bowl from the heat and set aside.
• 3.
  Add the egg yolks, vanilla, and 1/4 cup (1.8 oz / 50g) of the sugar to the chocolate mixture and vigorously whisk to combine. Whisk in the almond flour until thoroughly combined. It will look broken and separated, which is okay! Add 1/4 cup (2 oz / 57g) water and whisk vigorously until the mixture comes back together and looks smooth and glossy. Set the bowl aside.
• 4.
  In a separate clean, large, non plastic bowl, with a hand mixer, beat the egg whites and a pinch of salt on medium-low speed until the whites are broken up and frothy, about 20 seconds. Increase the speed to medium-high and continue to beat until the whites are foamy and opaque, about 30 seconds, then gradually add the remaining 3/4 cup (5.3 oz / 150g) sugar in a slow, steady stream, beating constantly. Once all the sugar is added, increase the speed to high and continue to beat just until you have a dense, glossy meringue that holds a stiff peak. Try not to over beat, or the whites will take on a dry, grainy texture and be difficult to incorporate.
• 5.
  Scoop a heaping cup of the meringue and set it aside for swirling on top of the cake. Scrape about half of the remaining meringue into the bowl with the chocolate mixture and fold gently until just a few streaks remain. Scrape in the rest of the meringue and fold just until you have a light, airy, evenly mixed batter. Scrape the batter into the prepared pan, then dollop spoonfuls of the reserved meringue across the entire surface. Use a skewer or toothpick to swirl the meringue into the batter and vice versa. Swirl a little or a lot; it’s up to you.
• 6.
  Bake the cake until the surface is risen and cracked, the meringue is light golden, and a skewer or cake tester inserted into the centre comes out shiny but clean, 1 hour to 1 hour 10 minutes. Remove the cake from the oven and place on a wire rack, then immediately run a paring knife or small offset spatula between the very top of the cake and the rim of the pan all the way around to loosen any areas that may be stuck (this will help the cake settle evenly as it cools). Let the cake cool completely. Cut around the sides again to loosen the cake, then remove the outer ring of the pan.