Heat 1/2 cup of the olive oil in a large saute pan over medium-high heat. When the oil is hot add the mushrooms and cook until they start to brown. Make sure not to crowd the pan or the mushrooms will steam instead of searing. Remove from pan and set aside.
Turn the pan to medium heat and add the remaining 1/2 cup olive oil, onions and garlic and saute for about 10 minutes. Add chicken broth and reduce by half. Add the cream and reduce by half. Add the rest of the ingredients, simmer for 10 minutes and season witth salt and pepper to taste.
Pour mixture into a fondue pot. Surround with seared mushrooms. Dip the mushroms into the mixture.