Mushrooms & chicken: Preheat the oven to 180º C fan bake. Grease a medium sized oven-proof dish. Melt 2 tbs butter in a medium pot. Finely dice 200g mushrooms and add to the pot. Cook for 5 minutes or until golden. Add 2 tsp crushed garlic, 1 tsp thyme, 1 tsp oregano, 1 tsp pepper and 1 tsp salt. Cook for a further 4-5 minutes, then remove from the pan. Add 2 tsp olive oil to the pan. Thinly slice the chicken breast and cook for 3-4 minutes per side. Once cooked, remove from the heat, roughly chop and set aside.
Pasta: Bring a large pot of water to a boil over high heat and boil 200g large pasta shells as per the package directions.
White sauce: Melt 1 tbs butter in a pot. Whisk in 1 tbs flour and cook for about 1 minute. Add 1/4 cup of white wine, and 1 cup of milk. Bring to a boil and stir for 3-4 minutes. Remove from heat and stir in 30g grated cheese until melted and the sauce is smooth. Add the cooked mushrooms, chicken and 50g baby spinach and mix well.
Assemble: Working with one pasta shell at a time, spoon 1 tablespoon of the mushroom/spinach cheese sauce mix into each shell, placing the filled shell into the baking dish as you go. Pour the remaining cheese sauce over top. Top with a 1/4 cup of grated parmesan, then bake for 15 minutes or until the top is golden. Serve immediately.