To another medium bowl, whisk together the flour, lemon pudding mix, baking powder, and baking soda.
2 ¾ cups all purpose flour, 1 3.4 oz instant lemon pudding mix, ½ teaspoon baking powder, ½ teaspoon baking soda
To a measuring cup, add the buttermilk then whisk in the lemon juice.
¼ cup buttermilk, ¼ cup fresh lemon juice
Add the dry ingredients and buttermilk to the butter-sugar mixture in multiple additions, alternating back & forth, starting and ending with the flour mixture and beating on medium speed. Scrape down the sides of the bowl as needed.
Pour the batter into the prepared bundt pan and bake for approximately 65 minutes or until a toothpick inserted into the center comes out clean.
Let cool for about 10 minutes then flip onto a wire rack to cool completely.
Cut & serve.
Notes
Store covered in plastic wrap or in an airtight container for 4-5 days at room temperature.