Heat the butter in a large skillet over medium high heat until melted, about 2 minutes. Continue cooking, swirling the pan constantly until the butter is a golden brown color and has a nutty aroma. Remove from heat and transfer to a bowl and put in your fridge until it sets again (about 2 hours) or the freezer for ½ an hour. (Here is a video on how to brown butter)

Remove the hardened browned butter from the fridge and let it get to room temperature. With the wire whisk attachment, beat the browned butter for one minute on medium-high. Add the brown sugar and whip until incorporated. Add the orange juice. Add the powdered sugar, ½ cup at a time, beating until incorporated. Add the sour cream, salt and vanilla. Whip for a few minutes until it is really fluffy. If the frosting gets too firm, you can add more orange juice, adding one tablespoon at a time.