In a medium heat-proof bowl, whisk the egg yolks until completely smooth.

In a medium saucepan, whisk together 1/3 cup of the sugar, the cornstarch and salt. Whisk in the milk. Place the saucepan over medium heat and cook, whisking constantly, until the milk starts to simmer, 5 to 8 minutes. Remove saucepan from the heat.

Ladle about 1/2 cup of the hot milk mixture into the egg yolks in a thin stream while whisking to keep the eggs from curdling. Pour the milk-egg mixture back into the saucepan and whisk to combine.

Place the saucepan over medium-low heat and cook, stirring with a rubber spatula, until the pudding starts to bubble and thickens, 1 to 2 minutes. Remove from the heat and stir in the butter pieces, 1 teaspoon of vanilla extract, and the almond extract.

Pour the pudding into a bowl (if some of the eggs have curdled in the pudding, strain it through a mesh strainer). Cover the pudding with plastic wrap, placing wrap directly on the surface of the pudding to prevent a skin from forming. Refrigerate for at least 2 hours or up to 2 days (the pudding will thicken as it cools).

Place half of the cake pieces in the bottom of a trifle dish or divide among six 12-ounce glasses. Top with half of the pudding, half of the strawberries and half of the raspberries. Repeat layers with the remaining ingredients. Cover and refrigerate for at least 4 hours or up to 1 day.

Shortly before serving, make the whipped cream: In a large bowl, combine the whipping cream, the remaining 1 tablespoon sugar, and remaining 1 teaspoon vanilla extract. Using a stand mixer or handheld electric beater, beat until medium peaks form (peaks slightly fall over). Dollop the whipped cream over the trifle and sprinkle with sliced almonds.