Preheat oven to 325ºF. On the stovetop over a medium-high heat melt butter in a Dutch oven. Season brisket on both sides with salt and pepper, and then add to Dutch oven and sear on all sides until golden brown. Remove to a plate.
Add in the onions and garlic and sauté until softened. Pour a few tablespoons of the apple cider into the pan to deglaze. Stir until all caramelized bits are lifted from the pan. Add in brisket and herbs and pour remaining apple cider over the top.
Bring to a simmer, cover and move to the oven. Roast the brisket at 325ºF for 2 1/2 to 3 hours or until tender, adding in apples 30 minutes prior to the end of cooking.
Remove Dutch oven and allow to cool. Drain fat from the top of the pot and discard. Remove meat, apples and onions and heat the remaining sauce over medium heat, stirring occasionally, until the mixture reduces and becomes a gravy. Add in brisket, apples and onions and cook until warm. Serve immediately.