3 large eggs
3.5 cups all-purpose flour
1 cup (2 sticks) butter, melted + 1/2 cup olive oil
1 cup sugar
1 Tsp vanilla extract
1 Tsp baking powder
1 Tsp salt
1-1.5 cups mini chocolate chips (your preference, I used semi-sweet and 1 cup)
Coarse sugar for sprinkling (optional)
1) By hand (vigorously) or machine, beat together the eggs, butter + oil, sugar, vanilla extract, and salt at medium speed until thickened, about 5 minutes. Then add the flour and baking powder and stir vigorously.
2) Next, mix in the chocolate chips and nuts. Cover and refrigerate for 2-3 hours (or overnight).
3) Preheat the oven to 350°F. Lightly grease TWO baking sheets (or line with parchment). Divide the dough into four even pieces. Shape each piece into a log, to form four even logs, about an 10" x 2" log. Place 2 logs on each greased (or parchment lined) baking sheet, leaving at least 2" between them--they WILL spread out. If they do touch in the oven, it's not a major problem...you can cut them apart easily. But try to avoid it if you can.
4) Sprinkle the shiny, buttery logs with coarse white sugar, as desired.
5) Bake the logs for about 30 minutes in the oven, until they solidify a bit and begin to brown and the edges and sides ONLY. You don't want them brown all over at this point. Remove them from the oven, and reduce the oven temperature to 300°F. Allow them to cool for 10 minutes.
6) Cut each log into 1/2" to 3/4" slices. Cutting them on a diagonal will make them longer. If you want shorter cookies, you can cut them straight across to yield shorter cookies.
7) Place the pieces close together (on edge) on the baking sheets, and return them to the oven for an additional 35 to 45 minutes, until you see more browning around the edges. The point is simply to bake them all the way through.
8) Remove from the oven, and cool the biscotti on the baking sheets.