Coffee Tortoni with Chocolate Sauce

Name: Coffee Tortoni with Chocolate Sauce
Ingredients: For the tortoni:; 3 egg whites (at room temp); 1/8 teaspoon cream of tartar; 1 cup sugar, divided; 2 cups heavy cream; 1/2 cup cold espresso; 3 tablespoons Kahlua; 1/2 teaspoon vanilla extract; 3/4 cup slivered almonds, toasted; 1/4 cup slivered almonds, toasted and chopped very fine; Chocolate Sauce; 4 ounces bittersweet chocolate; 1/3 cup heavy cream; 2-3 tablespoons agave nectar (or corn syrup); 1/2 teaspoon almond extract; Pinch sea salt