Whip heavy cream until stiff peaks form (you can use a stand mixer or hand beater for this).
Combine simple syrup, mascarpone cheese, and almond extract in a small mixing bowl, then fold in whipped cream.
Dip ladyfingers into the simple syrup mixture one at a time, then layer half of it on the bottom of a 9x13-inch baking dish that has been lined with plastic wrap. Drizzle simple syrup over them. Spread mascarpone mixture evenly over ladyfingers then repeat step 3 to create another layer. Finish with a final layer made up of simple syrup-dipped ladyfingers.
Sift cocoa powder on top, followed by drizzling any extra simple syrup you may have leftover.
Cover tiramisu tightly with plastic wrap, then place in the freezer for 4 hours.
Serve simple tiramisu cake chilled by removing from the baking dish and cutting it into pieces.