- In a skillet, sauté the sausages in butter until brown. Take the sausages out.
- Sprinkle the flour into the hot butter, stirring the mixture until it thickens and turns golden. Stirring continuously, gradually add the beer and the stock. The sauce should be thick and have no lumps. Add the vinegar and bay leaf and simmer for 10 minutes. Add the capers, lemon juice and lemon zest. Season to taste with salt and pepper.
- Place the sausages back in the skillet and simmer in the sauce for another 5 minutes, or until the sausages are warmed through, over low heat.