This is great with bread.
1 tablespoon butter
2 tablespoons minced onion
a couple of handfuls of sliced mushrooms, any kind (shittake and portobello are especially good)
2 tablespoons flour
1 cup chicken broth
1/2 cup heavy cream
Saute onion in butter until wilted, add mushrooms and stir until they give up their liquid. The trick is not to crowd the pan. Do a few mushroom slices at a time if necessary. Cook until the liquid evaporates. Sprinkle with flour, whisk rapidly. Add broth, continue whisking until blended and smooth. Cook, stirring occasionally, another 15 minutes. Add cream, simmer 5 minutes more.
I've tried making this with reconstituted dried mushrooms (advantage: much cheaper than fresh) and the fresh really do taste better. But you don't have to use fancy expensive mushrooms; plain old white button mushrooms will do just fine if that's what you can afford. If the final result with those is a little bland for you, you can add salt or fresh thyme to jazz it up a bit.