Sweet potato gratin with caramalized onions

This dish serves 12 or a family of four, several times! This is part of the Thanksgiving dinner from Fine Cooking magazine... continued...

It's Thanksgiving so nobody ordered diet food!

You will need:

4 Tbsp unsalted butter
6 cups sliced onions
salt and pepper to taste
2 cups whipping cream (told you it wasn't diet food)
3 sprigs fresh thyme
Zest from 1 orange
1/8 tsp cayenne pepper
5 medium sweet potatoes sliced 1/8 inch

Topping
1 cup chopped pecans, toasted
2 tbsp fresh breadcrumbs
2 Tbsp freshly grated Parmesan cheese

Heat the butter until foaming and add onions. Cook over medium low for ~40 minutes until they are nicely browned. Add salt and pepper to taste. Set aside and allow to cool.

Heat the cream, thyme, orange zest and cayenne in a saucepan... boil, remove from heat and steep for 15 minutes.

Butter a 9 by 13 baking pan. Arrange overlapping layers of potatoes. Add half the onions, season with salt and pepper and drizzle 1/3 cream mixture over top. Repeat with potatoes, onions, salt, pepper and cream. Top with remaining 1/3 of potatoes and pour remaining 1/3 of cream on top.

Cover with foil and bake at 375 F for and hour. Remove foil and bake another 40 minutes until top is lightly browned and bubbly. Add pecan mixture and bake another 10 minutes. You can prepare this ahead. Refrigerate after first hour of baking. Finish the final baking without the foil cover the day of your Thanksgiving meal.