Heat 2 tablespoons of butter in a large skillet or Dutch oven. Once melted, add the bratwursts and cook about 5 minutes on each side. Once the bratwursts are in the pan, do not move them around until it is time to flip them over. The goal is to get a deep brown crust on two sides before adding the braising liquid. They will not sear properly if they are moved too often during the browning stage. Once you have a nice golden crust on 2 sides of the bratwursts, remove them from the pan and set aside.

Add the remaining 2 tablespoons of butter to the pan and, once melted, add the onions and apples. Cook on low for 5-10 minutes until slightly caramelized.

Add the hard cider, brown sugar, mustard, salt, and pepper, stirring to combine. Return the bratwursts to the pan. Bring to a boil, then reduce heat to low and cover with a lid. Cook on low for about 15 minutes, or until the brown sugar starts to form a syrupy glaze and the braising liquid has been reduced by half.

Garnish with the fresh sage and tarragon.