In a saucepot set over medium heat, melt the butter. Add the onions and garlic, and saute for 3 minutes. Add the sausage and cook for 5 minutes. Add the flour to create a roux. Cook, stirring continuously, until the roux is a rich caramel color and smells nutty, 5 minutes. Add the stock and coffee, and stir. Add the paprika, black pepper and cayenne. Cook, stirring occasionally, until thickened, about 15 minutes. Finish with the cream and season with salt.