Preheat oven to 180C (160 fan-forced). Boil shells to al dente. Remove from heat and allow to cool until able to be touched.
Combine sauce ingredients in a pot over low heat. Stir to combine.
In a bowl, mix together cheeses with spinach and add pepper as needed.
In a baking dish, spoon sauce mixture across the surface of dish 1cm deep. Place shells in the dish open side up. Spoon cheese and spinach mixture forex bank västerås öppettider
into each shell until full but not overflowing.
Cover the baking dish with aluminum foil and bake for 40 min to 1hour or until piping hot.