Preheat the oven to 350° F. Grease a 9x9 inch baking pan. Zest the lemon before using.
In a small bowl combine milk and lemon juice. Set aside and let sit for 5 minutes.
In a large mixing bowl, combine melted butter, sugar, and vanilla extract and mix well. Add in egg and whisk for 1-2 minutes until smooth and creamy.
Add buttermilk to the mixture and whisk together.
Add in the flour, salt, and baking soda and mix together until batter forms and flour pockets are gone. Fold in cranberries gently, careful not to overmix.
Transfer to prepared baking pan, spread batter evenly and sprinkle 1-2 Tablespoons of sugar on top. Bake on a middle rack for 35-45 minutes, until inserted toothpick comes out clean. Sprinkle the lemon zest on top. Cool for 10 minutes, slice and serve. Enjoy!
Notes
Make Ahead: Prepare recipe as directed, cover with plastic wrap, and refrigerate overnight. Let rest at room temperature while oven is reheating and bake. Add 5-10 minutes to baking time since batter will be cold from fridge. If using a glass or ceramic pan, baking may take 5-10 minutes longer than listed in recipe.