Heat oven to 350°F. Lightly grease baking sheets. Combine dry ingredients. Cream butter and sugar together 5 minutes till light and fluffy. Add eggs one at a time and beat till well combined. Stir in vanilla and lemon peel. Combine Nestea and water; stir till tea is dissolved. Add to sugar mixture. Gradually stir in flour mixture and nuts. Shape dough into two 11x2 inch logs on each baking sheet; smooth sides with rubber spatula. Bake 20 minutes till toothpick inserted in center of each log comes out clean. Slide logs onto cutting board and cut diagonally with serrated bread knife into 1/2 inch thick slices. Return to baking sheets cut sides down. Bake 20-25 minutes longer, turning over halfway through. Remove to racks to cool completely.