Place hazelnuts and 1 1/2 cups water in blender. Blend until fine, 30 seconds. Set a fine sieve over a small bowl, and pour blended mixture through. Reserve puree left in sieve for Chocolate Torte. In another bowl, whisk together 1 cup sugar and cocoa powder; set aside.
Place 1 cup nut liquid in saucepan with vanilla seeds, margarine, remaining 1 cup sugar, and salt. Bring to full boil. Whisk in cocoa mixture; return to boil. Remove from heat; let cool 30 minutes. Store in airtight container; refrigerate.