Preheat oven to 325°F (165°C).
Season the duck legs with salt and pepper. Place them in an ovenproof pan and pour the beer over to cover halfway.
Cover the pan and braise the duck legs in the oven for about 75-90 minutes until tender and the skin is browned.
Once cooked, remove duck legs and let rest. Skim any excess fat from the braising liquid and reduce it on the stove to a thicker sauce if desired.
In a small bowl, crumble the cake slice into fine crumbs.
In another bowl, combine the vanilla ice cream with the finely diced dill pickle and chopped pecans. Stir gently to combine into a chunky, creamy mixture.
Add the fresh chopped dill into the ice cream mixture for an herby burst.
To serve, place a duck leg on a plate and drizzle with some of the reduced beer sauce.
Add a scoop of the dill pickle pecan ice cream mixture on the side and sprinkle with the cake crumbs for texture.
Optionally, serve with a few ice cubes on the side to keep the unique dessert chilled and refreshing.