For the cake: Turn on the oven to 325°. Grease a 2-inch deep, 10-inch round cake pan or springform pan. Line the bottom with a round of parchment paper, then grease the paper and flour it all -- pan and paper. Spread the almonds on a baking sheet and toast in the oven, stirring them occasionally, for about 12 minutes, until aromatic and golden. Cool, then transfer to a food processor along with the flour. Run the machine until the nuts are pulverized. In a small pan, melt the butter over medium heat, stirring and swirling until nut brown, about 5 minutes. Remove from the heat, cool a little, then stir in the vanilla. Raise the temperature of the oven to 350°.

Combine the eggs, ¾ cup of the sugar, and the orange zest in the large bowl of your electric mixer (you will need a heatproof bowl, preferably stainless steel), then choose a saucepan that the mixer bowl will fit snugly into. Fill the saucepan with 1 inch of water and bring to a simmer. Set the mixer bowl over the simmering water (you'll need to regulate the heat so the water no more than simmers), and whisk for several minutes, until the mixture is very warm to the touch and foamy, and the sugar is completely dissolved. Transfer the bowl to the electric mixer and beat for a full 5 minutes (the mixture will be as thick as whipped cream that almost holds peaks). With the mixer on the lowest speed, add the almond mixture a couple spoonfuls at a time, letting one addition just disappear before adding the next. Thoroughly mix¼ cups of the cake batter into the butter mixture. Then, in 2 additions, use a whisk to fold the butter mixture into the remaining cake batter,

Immediately and gently scoop the mixture into the prepared pan and bake until the cake feels slightly springy on top and the sides just begin to pull away from the pan, about 35 minutes. Cool 10 minutes, then turn out onto a rack and cool completely.

For the flavoring: Mix ¾ cup of the cream with the evaporated milk and the cajeta in a small bowl. Slowly brush or spoon half of the mixture over the cake while on the cooling rack. Carefully invert your serving plate over the cake and flip the two. Remove the cooling rack from what is now the top and slowly brush or spoon on the remaining mixture. (Soaking the cake will take 10 to 15 minutes, letting each addition soak in before adding more.)

Frosting the cake: With an electric mixer on medium-high speed, beat the remaining 1¼ cups of the cream with the remaining 2 tablespoons of the sugar and the orange liqueur until very stiff. Spread the whipped cream over the sides and top of the cake. Save a little to pipe a border around the top and bottom edges of the cake. Refrigerate until ready to serve.

Advance prep: The cake layer can be made several days in advance, wrapped in plastic and refrigerated; it may be wrapped and frozen for up to 3 months. The cake can be soaked a day ahead, but do not frost until the day you are serving.