With a wet paper towel clean portobello mushrooms and cut into large chunks, about the size of the gnocchi. Heat a large frying pan over medium high heat and sauté both mushrooms until they begin to sweat about 4-5 mins. Add sun dried tomatoes, wine and 1/4 cup of the chicken broth. Simmer until tomatoes are soft, about another 4-5 mins. Take off heat and set aside.

In a large sauce pan melt butter over med/high heat. Add diced onion & sauté until soft and lightly golden brown. Add garlic and herbs, sauté for another minute. Add flour and whisk consistently, cooking for an additional 2 mins. It will look like a thick and clumpy paste at this point. Slowly pour in remaining 3 cups chicken broth and milk. Continue whisking and bring to a boil. Once boiling add gnocchi and mushrooms. Simmer for 4 minutes or until gnocchi is cooked, making sure to stir a few times. While soup is simmering, temper yogurt with hot liquid from soup. Once gnocchi is fully cooked, take off of heat and stir in yogurt.

Serve immediately.