Preheat the oven to 350 degrees.
Lightly grease a 9×5 loaf pan with butter.
Combine flour, baking soda, baking powder, and salt well in a medium-sized bowl.
Cream butter and brown sugar for 3-5 minutes with an electric mixer until light and fluffy.
Beat in room temperature eggs one at a time.
Once eggs are combined, add room temperature maple syrup, yogurt, stirred sourdough starter, lemon zest, and lemon juice.
Fold in dry ingredients a bit at a time until just incorporated.
Pour into a greased pan and bake for 60 to 65 minutes. Test bread at 55 minutes with a toothpick or cake tester.
Allow to cool completely in the loaf pan for one hour.
While it is cooling, create the glaze by whisking together the lemon juice and powdered sugar.
Once the loaf is cooled, drizzle the lemon glaze over the top of the loaf and enjoy!
Be careful not to over mix the batter or your pound cake will end up dense and tough.