Melt the butter in a small frying pan over high heat. Once it begins to foam, stir it and watch it carefully, it will brown in 1-2 minutes. Stir the butter a few times to ensure it browns evenly. Remove the pan from the heat. Add the avocado oil to the pan then and set it aside for the butter to cool slightly.
¼ cup salted butter, ¼ cup avocado oil
In a medium-sized bowl, whisk the maple syrup, balsamic vinegar, apple cider vinegar, and dijon mustard. Slowly drizzle in the brown butter and oil, whisking the entire time. Once all the oil and butter have been added, whisk the dressing quickly for several seconds so it becomes creamy.
1 tablespoon maple syrup, 1 tablespoon balsamic vinegar, 1 tablespoon apple cider vinegar, ½ tablespoon dijon mustard
Store the dressing at room temperature until you are ready to use it.
Notes
Make sure to choose an oil that does not harden in the cold - grapeseed, canola, and sunflower oil are a few to choose from.