My cousin Linda made my day when she sent me our Oma’s recipe for Schoko-Nusskuchen along with the note, “This is the cake Oma always baked for our Birthdays.” This simple little cake may not be a fancy Torte, but flavorwise, it packs an amazing punch, reminding me of my favorite mid-day pick-me-up treat, a Hanuta. It’s hazelnut and chocolate,…