Thaw pastry sheets, and overlap in a square/ diamond shape on a sheet of baking paper so they look like a star. Place in your slow cooker in a pie shape.
Fry off the bacon and onion until brown (optional), allow to cool.
Beat eggs & cream together in a large bowl, then add spinach, bacon/ onion mix, cheese and salt and pepper until mixed in.
Pour into pastry base, place towel over the top and cook on high for 2.5 hours turning the quiche once. (Pulling the whole thing out by the baking paper and turning it around)