Heat 2 tablespoon oil and 1 tablespoon butter in a large skillet over medium-high heat. Add mushrooms, ½ teaspoon salt and ¼ teaspoon pepper. Cook for about 10 minutes till mushrooms have released their liquid and are lightly browned. Variation - see the note below if you want to add more mushroom flavour with reconstituted porcini mushrooms.

Transfer to a large bowl.

Bring a large pot of salted water to a boil and cook gnocchi according to manufacturer's instructions. Do not overcook. Cook just until they rise to the surface. Remove with a slotted spoon and reserve cooking water. Drain gnocchi well and transfer to a large bowl. Add remaining tablespoon oil to the gnocchi, stir well and allow to cool.

While gnocchi is cooking melt remaining butter in the skillet over medium heat. Add onion, rosemary and ¼ teaspoon salt. Cook for about 5 minutes til softened. Reduce heat and cook another 20 minutes til golden.

Add garlic to the onions in the skillet and cook another 3 minutes. Increase heat to medium-high and add wine. Bring to a boil, scrape up any brown bits from the skillet bottom and cook unti wine has reduced by about half.

Heat cream lightly in the microwave. Sprinkle the flour over the onion mixture and stir to coat well. Add the cream and cook about 5 minutes until cream thickens. Check seasoning and adjust salt and pepper to taste.

Pour the cream sauce into the mushrooms in the bowl. Pour the mushroom sauce over the gnocchi. You want it to be quite saucy so add a bit of the cooking water to moisten the mixture if desired. (Some of the liquid will be absorbed during baking.)

Preheat oven to 350 degrees. Spray a 9 cup casserole dish with cooking spray. Add the gnocchi mixture and bake covered for about 45 minutes. Remove cover and bake another 10 minutes to allow top to brown.

Serve with Parsley and Parmesan for garnish.

To make ahead and freeze - divide mixture between desired number of casserole dishes, sprayed with cooking spray. Cover and freeze up to a month. To serve allow gnocchi to thaw in the fridge at least 12 hours or up to 2 days. Continue to cook as per above. Note: If mixture seems dry add a little more warm cream and stir well before putting in the oven.

Variation: If you are a mushroom fan consider reconstituting .5 ounce of dried porcini mushrooms in boiling water for 20 minutes. Rough chop the reconstituted mushrooms and add to the pan with the sliced creminis. You can use some of the mushroom water instead of the cooking water, being careful not to get any sediment from the bottom, if you need to make the mushroom mixture more moist when adding the gnocchi.