Supper Onion Pie

From How to Be a Domestic Goddess: Baking and the Art of Comfort Cooking  

by Nigella Lawson

contributed by Richard Kelsey

Preheat the oven to 400F. 

Filling: 

Peel 4 medium red onions, halve them, then cut each half into 4 segments each. Heat 1 Tbs. olive oil and 1 Tbs. butter in the pan, then add the onions and cook over a medium heat, stirring regularly, for about 30 minutes; they should be soft and tinged with color. Season with salt and pepper, and add 3-4 springs thyme, de-stalked. Turn into a 9-inch pie plate, buttered, or 8 to 10-inch cast-iron skillet. Sprinkle 2 oz. sharp cheese 

(Cheddar or Gruyere) grated, over onions.  

Topping: 

Place 1 2/3 c. flour, 1 tsp. baking powder, and 1 tsp. salt in a bowl with additional 3 oz. sharp cheese, grated. Pour ½ c. milk into a large measuring cup and add 3 Tbs. melted butter, ½tsp. dry mustard, and 1 large egg, beaten. Mix well and pour into the flour mixture. Mix to a dough using a fork, a wooden spoon, or your hands;  it should be quite sticky. Tip dough onto a work surface and press into a circle about the size of the pie dish. Transfer it to the dish, pressing it to seal the edges. Bake for 15 minutes.

Turn down to 350F and bake additional 10 minutes. Dough should be golden and crisp on top.

Let it stand for a couple of minutes, then cover with a large plate and turn upside-down. Place on a flat surface and remove the dish. Serves 6.