The easiest way to enjoy these is on toast as I did, but I have served this in the past over barley groats cooked in stock and also tossed into pasta. It also works in a pinch as an omelet filling.
I usually make this with grain mustard, but I am out so I used mustard seed, Dijon mustard and a splash of rice wine vinegar instead. If you have grain mustard then definitely use that. If not, regular Dijon mustard and a splash of vinegar will work well; the plain mustard seeds added very little here.
1 cup assorted mushrooms, chopped into bite-sized pieces (I used a mixture of oyster and baby Bella mushrooms here. Shiitake would be a great addition as would field mushrooms if you know what you are doing.)
1 clove of garlic, very finely chopped
1 tsp butter
1/4 tsp sweet paprika
1/2 tsp Worcestershire sauce
Splash of brandy, cognac or sherry (sherry tastes best with mushrooms, but I do not keep it on hand)
2 tsps grain mustard
1 Tbsp sour cream
Salt to taste
Add the butter to a pan along with the garlic and the paprika. Turn the heat to low and let the butter melt into the garlic and spice.
Raise the heat to medium and add the mushrooms, some salt and a teaspoon or so of water. Cook, stirring occasionally, until the mushrooms are cooked through and the liquid has been absorbed.
Add the alcohol to the pan and stir to combine and cook off the alcohol. Add the Worcestershire sauce and stir to combine.
Measure in the mustard and the sour cream and cook, stirring constantly, until the mustard has melted into the sour cream and the sour cream is heated through and bubbling away around the sides of the pan.
For best timing, if serving this over toast, place the toast in the toaster just after you have added the Worcestershire sauce to the pan.