Mashed Potato Gratin with Garlic and Onions Recipe

Directions:

1. Remove the papery covering of the garlic heads, but do not peel and do not separate the cloves.
2. Wrap well in foil and put them in the oven.
3. Put the onions on a double sheet of foil, but do not wrap them; put them in the oven.
4. Pierce the potatoes in several places with a thin skewer or the tines of a fork.
5. Place them directly on the oven rack.
6. Bake the garlic for one hour and the onions and the potatoes for an hour and a half at 425F degrees.
7. After an hour pull out the garlic heads, unwrap, and let cool for 5 minutes.
8. Separate the cloves and squeeze them over a bowl so the softened garlic pops out into the bowl.
9. After 1 1/4 hours, pull out the onions and potatoes.
10. If the onions are not very soft (almost collapsed) put them back in for a few minutes.
11. Perforate the potatoes lengthwise and crosswise with the tines of a fork and squeeze.
12. Scoop the potato flesh into a bowl and mash it with a potato masher.
13. With a sharp knife, cut off the stem and root ends of the onions.
14. Remove the skin and the first layer.
15. Put the onions in a food processor and puree.
16. Combine the potatoes, garlic, onion, 1/4 cup of cream, and salt and pepper in the bowl of a mixer.
17. Beat (with the paddle blade) until smooth and blended, then scrape the mixture into a large gratin bowl.
18. Sprinkle the top with cheese.
19. (The recipe can be made ahead to this point and kept in the refrigerator, covered, for a day or so. Bring to room temperature before proceeding.) Reduce the oven temperature to 350 degrees F.
20. Pour the remaining cream over the mixture.
21. Bake, uncovered, for 40-50 minutes , or until the top is browned and bubbly and the cream has cooked down to a very thick suace-like consistency.
22. Try to arrange to have some leftovers; this is very good when it is cold.