To make the filling: In a medium-sized saucepan, stir together 2 cups (454g) of the milk, the sugar, and the salt. Bring to a simmer over medium heat, stirring to dissolve the sugar., Meanwhile, whisk the cornstarch, egg yolks, and whole egg with the remaining 1/2 cup (113g) milk., Whisk some of the hot milk mixture into the egg yolks/cornstarch to temper the yolks. This keeps them from turning to scrambled eggs when you add them to the simmering milk., Pour the egg/milk mixture back into the remaining simmering milk, pouring it through a strainer to capture any bits of egg. Bring to a boil over medium heat (this may happen very quickly), stirring constantly with a whisk. Cook for 2 minutes, stirring constantly; the mixture will thicken significantly., Remove from the heat, and stir in the vanilla extract., Transfer the filling to a heatproof storage container, and top it with a piece of buttered plastic wrap (make sure it touches the top of the filling so it doesn't develop a skin). Refrigerate until cool, or for up to several days., Preheat the oven to 350°F. Lightly grease two 8" round cake pans. Or lightly grease the pans, line with parchment rounds, and lightly grease the parchment as well., To make the cake: In a medium-sized mixing bowl, beat together the butter, sugar, salt, and egg yolks until well combined. Scrape the bowl, and beat briefly to incorporate any sticky residue., Beat in the vanilla, milk, baking powder, and flour; the batter will be stiff., Spread the batter in the prepared pans (it will barely cover the bottom of the pans; that's OK)., To make the topping: Using an electric mixer or stand mixer with a whisk attachment, beat the egg whites until foamy; gradually add the 3/4 cup (149g) sugar and continue to beat until the meringue is smooth, glossy, and somewhat stiff (but not stiff enough to form rigid stand-up points)., Spread the meringue on the cake batter. Sprinkle the almonds over the meringue. Mix the cinnamon with the sugar, and dust on top., Bake the cakes for 30 minutes, until the almonds are lightly browned. The cakes will puff up significantly; don't worry, they'll settle as they cool., Remove the cakes from the oven, and allow them to cool for 15 minutes. Carefully and thoroughly loosen the edge of each cake, and gently turn it out onto a rack to cool completely. The best way to do this is to place a flat object (a giant spatula, a small baking sheet) atop the pan, and to turn everything over. Lift the cake pan off the cake, then place a cooling rack against the bottom of the cake. Turn everything back over again, so the rack is on the bottom. Some of the almonds will fall off during this process; just sprinkle them back on top., When you're ready to finish the cake, remove the pastry cream from the refrigerator. Stir it gently, just to loosen it up enough to spread; stirring too vigorously can break it down and turn it watery. It'll probably have a few lumps; that's OK. For slightly richer filling with greater volume, whip 1/2 cup (113g) heavy cream to stiff peaks, and gently fold it into the pastry cream. Again, don't beat the pastry cream; it'll be a bit lumpy, but that won’t affect the taste., To assemble the cake: Place one of the cake layers, meringue side up, on a serving plate. Spread with the filling. Add a layer of fresh berries. Top with the second cake layer, meringue-side up., Serve immediately, or refrigerate until serving time.