Chop your mushrooms in small pieces in varieties of sizes smaller than a pea either by hand or food processor.
Place butter in a skillet and melt it. Sauté the mushrooms Until most of the water has evaporated.
Mix in the flour until incorporated
Add the broth and spices. Bring to a boil.
Drop the heat to low and whisk in the half and half allow it to thicken for 3 minutes
Remove and let cool. Will continue to thicken as it cools.