Cool the cakes completely before assembling and frosting.
Buttercream
In the bowl of your stand mixer fitted with the whisk attachment, beat the butter for 1 minute until smooth.
Separately, combine the powdered sugar, meringue powder and salt. With the mixer on low, add the sugar mixture by spoonfuls, mixing until combined but clumpy.
Add the extracts, and increase the speed to medium (#4-6 on a Kitchen Aid). Whip for about 5 minutes, scraping the bowl several times, until very light and fluffy. If the buttercream seems too thick for spreading, beat in a little milk, 1 tablespoon at a time. Turn the speed down to "stir" and mix for 1 minute to get rid of air bubbles.
Fold in the chopped almonds
Assembly
Remove the cooled cakes from the pans, and place one cake on a cake board or cake pedestal.
Spread the cake with a thin layer of the almond pastry filling.Spread a layer of buttercream on top of the almond pastry filling.
Add the next layer of cake, and spread with almond pastry filling, followed by buttercream.
Frost the cake all over with a final coat of buttercream, smooth it out as much as you like, and chill the cake for 30 minutes.
Ganache
Chop the chocolate and scrape it into a bowl.
Warm the cream just until hot and beginning to simmer, then pour the hot cream over the chocolate. Stir until it comes together into a smooth, creamy ganache.
Pour the ganache on top of the cake, and use a small offset spatula to spread the ganache out, pushing it over the edges of the cake so it drips down the sides.
Let the cake sit at room temperature for about an hour for the ganache to set.
Keyword Cake, Chocolate, Chocolate Almond, High Altitude Cake