In a medium saucepan, combine the milk, vanilla, and 1 tablespoon of the sugar. Heat over medium until just simmering.
In a separate bowl, whisk together the egg yolks, remaining sugar, and cornstarch until smooth. Gradually pour the hot milk into the egg yolk mixture, whisking constantly to temper the eggs. Strain the mixture back into the saucepan and cook over medium heat, stirring constantly, until thickened and bubbling. Let it bubble for 20 seconds, then remove from heat. Transfer the cream to a bowl, press plastic wrap directly onto the surface, and refrigerate until fully chilled, about 1 to 1½ hours.
Preheat the oven to 320°F (160°C), and grease a 8-inch (20 cm) ring mold or round cake pan with butter.
In a stand mixer fitted with the whisk attachment, beat the egg whites and salt on medium speed for 1 minute. Gradually add the sugar and continue beating until stiff, glossy peaks form. Gently fold in the almond flour and powdered sugar with a spatula until the batter is smooth and airy. Pipe or spread the batter into the prepared pan, forming higher edges and a slightly concave center to hold the cream.
Bake for 25–30 minutes, or until lightly golden and set. Let cool completely.
Whisk the chilled pastry cream until smooth.
In a stand mixer, whip the heavy cream to soft peaks. Gently fold the whipped cream into the pastry cream in three additions until fully incorporated and silky. Spoon or pipe the diplomat cream onto the cooled dacquoise, spreading evenly.
Arrange the sliced strawberries on top and scatter with toasted almonds. Dust with powdered sugar just before serving, if desired. Serve immediately or chill until ready to enjoy.