In a medium bowl, combine thawed peaches, tarragon leaves, and orange liqueur. Set aside to macerate.
In a medium mixing bowl, use a hand mixer to mix mascarpone cheese and sugar until creamy. Whisk in thawed whipped topping.
Divide half of the mascarpone cream among 6 parfait glasses or large martini glasses. Top with macerated peach and tarragon mixture. Sprinkle peaches with crushed biscotti and top with remaining mascarpone cream. Scatter almonds over and serve.