Melt butter in the saucepan over medium heat. Saute the onions and add the mushrooms.

In a separate bowl, mix 2 cups of chicken broth with the flour and seasonings. Pour into the mushroom mixture and mix thoroughly.

Pour the remaining chicken broth into the mixture. Wait until it boils and thickens.

Change to lower heat and mix in the half-and-half cream. Let it simmer, and make sure to mix once in a while.

After 10-15 minutes, turn off the heat and serve. Enjoy your homemade cream of mushroom soup.