Port wine mushroom sauce

Whenever I go to the store part of me keeps an eye on the wine section--specifically port wine. The first time I had it, I loved it because it was so sweet and I knew it would be great with dessert and for cooking in general. Unfortunately, the one time I buy port wine and taste it, I wasn't as delighted as I was the first time and I was rather disappointed. I probably chose a bad vineyard...label...um...whatever you call it. So I decided to look up recipes that use port wine instead of having to suffer through drinking the entire bottle on my own. I modified a recipe found at this website:  <http://www.cdkitchen.com/recipes/recs/1166/Bistro-Chicken-With-Port-Mushr121118.shtml>. I didn't have all the ingredients it called for so I made some of my own adjustments and substitutions:

Cooked the chicken separately and served over penne

Port Wine and Mushroom Sauce

Ingredients:

• 1/2 cup onion diced
• 1/2 tbsp butter
• 1 tbsp olive oil
• ~6 oz baby bella mushrooms, sliced
• 1 tsp flour
• 1/2 cup port wine
• 3 tbsp milk
• 1/4 tsp nutmeg
• salt and pepper to taste

Preparation:

1. Melt the butter in a large pan and add the olive oil. 
2. Add the onion and the mushrooms and cook until onions are clear.
3. Add the rest of the ingredients to the pan except for the flour.
4. Let about half of the port wine evaporate or let evaporate until you get the amount of sauce that you want.
5. Add flour and stir to make sure the flour doesn't clump together.

I need to try this recipe again because I used a sweet vidalia onion instead of a regular onion so the sauce became too sweet. I also want to try adding the chicken to the sauce while the sauce is cooking instead of cooking the chicken separately so that the flavors of the sauce can get cooked into the chicken.