In a large bowl, stir together cake mix and pudding mix. Crumble the dried tarragon into a fine powder and mix with the cake and pudding mixture. Make a well in the center and pour in lemon-lime soda, lemon juice, eggs and oil. Beat on low speed until blended. Scrape bowl, and beat 4 minutes on medium speed. Pour batter into prepared pan.
Bake in the preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.
