My scalloped potatoes are Jansson's Temptation. You could leave out the anchovies/sprats, sub ham or sundried tomatoes instead. I love these. I don't always put the breadcrumbs on top and I slice the potatoes in "rounds" instead of matchsticks (if you search on the Internet, you will find different versions of this). I do always put roasted garlic in mine with the onion layers.
Jansson's Temptation (Janssons Frestelse) Recipe - Allrecipes.com
I saute the onions in butter for about 5 minutes (until soft) before adding them to the pan. I cook them for 15 minutes at 425 and then reduce the heat to 375. When I reduce the heat, I usually add more cream to top up the potatoes.