Ingredients:
Mix flour, baking powder and baking soda in a medium bowl; set aside. Mix eggs, vanilla and salt in a small bowl; set aside. Microwave butter on high power until just melted but not hot, 30 to 45 seconds; set aside. Mix brown and granulated sugars in a large bowl. Add butter and oil; stir until smooth. Add egg mixture and stir until smooth and creamy. Add dry ingredients and stir until smooth. Stir in chocolate and optional nuts. Using a 1½-ounce (3 Tbs.) ice cream scoop, spoon 16 dough balls onto a pan that will fit in your freezer. (Don't worry if the dough balls are crowded. They pull apart when frozen.) Freeze until dough is hard, about 30 minutes. (Once dough balls are frozen, they can be stored in freezer bags up to 3 months and baked as desired.)
Meanwhile, adjust oven rack to upper middle position and heat oven to 400 degrees. Working in half batches, place 8 frozen dough balls onto a parchment-lined cookie sheet. Bake until set, but not brown, 8 to 10 minutes. Reduce oven temperature to 350 degrees. Continue to bake until cookies are golden-brown around the edges and lightly brown on the top, about 10 minutes longer. Let cookies cool on cookie sheet. Repeat, preheating oven to 400 degrees again before baking second batch.
Cookies can be stored in an airtight container up to 5 days.
Servings: 16 large cookies. Per cookie: 328 calories, 43g carbohydrates, 3g protein, 17g fat (9g saturated), 1g fiber, 295mg sodium.