In a pot boil the potatoes with skin-on. In a pan caramelize the onions in oil.
Melt 5 tbsp butter with garlic to brush on top of potato mixture. Combine potatoes, cream, cheese and onions then mash (should be a bit chunky.)
Place potato mixture in large baking dish or ramekins and bake at 400 degrees until golden brown on top. Dust with paprika.