Bratwurst in Biersoße or Stolzer Heinrich (lit. Proud Henry) is a traditional dish originating from East Germany. The dish is usually made with a combination of bratwurst, dark beer, oil, sugar, salt, pepper, and spiced cookies that are used as a thickener for the sauce.
The sausages are boiled and sautéed in oil over medium-high heat until browned on all sides. The pan is deglazed with beer, and the cookies are added to the pan. The mixture is simmered until the cookie bits dissolve. The sauce is seasoned with sugar, salt, and pepper, and it's then poured over the bratwurst.