1. Preheat the oven to 350 degrees Fahrenheit. Grease two baking sheets.
2. In the bowl of an electric mixer, cream together eggs, sugar, and oil. Add vanilla and baking powder. Add flour, one cup at a time. Slowly mix in chocolate chunks and walnuts.
3. Form dough into four large oval-shaped mounds. (If the dough is a bit sticky, wet your hands/gloves before you begin shaping the dough.) Place onto greased baking sheets. Bake for 25 to 30 minutes. Let cool for 10 minutes.
4. Slice into 1/2-inch biscotti strips. For crunchier biscotti, return to oven for an additional five minutes. Let cool.
5. Melt baking chocolate. Drizzle over biscotti and sprinkle with cookie crumbs.