Chocolate- and Almond-Dipped Sandwich Cookies

1/4 cup slivered almond s

1 cup sugar

1 cup (2 sticks) unsalted butter , room temperature

1 large egg yolk

1 1/2 teaspoons vanilla extract

1/4 teaspoon salt

1 1/2 cups all purpose flour Filling

1 cup whipping cream

12 ounces bittersweet (not unsweetened) or semisweet chocolate , chopped garnish

6 ounces bittersweet (not unsweetened) or semisweet chocolate , chopped

1 1/4 cups slivered almond s (about 5 ounces), toasted, chopped