Potato And Spinach Gratin - cooking recipe

Ingredients

4 lb potatoes, peeled
4 lb spinach, cleaned
3 None onions, peeled and finely diced
2 cloves garlic, peeled, finely chopped
6 tbsp butter or margarine
1/2 cup all purpose flour
2 cup vegetable stock
2 cups + 5 tbsp skim milk
1 1/2 cup Gouda, grated
3/4 cup Parmesan, grated
2 None egg yolks
1/3 cup pine nuts

Preparation

Preheat oven to 400\u00b0F. Place potatoes in a large pot of water. Bring to a boil and cook for 20 mins.
While potatoes are cooking, melt 2 tbsp butter in a saucepan and saute two-thirds of the onions and garlic. Add spinach in batches, cover and cook until wilted. Season and cook for 2 mins. Drain potatoes, leave to cool, and slice.
To make the sauce, melt 4 tbsp butter and cook remaining onions and garlic until soft. Sprinkle over the flour and cook briefly. Pour in stock and 2 cups milk. Bring to a boil while stirring, then simmer for 5 mins. Add half of the cheeses and stir until melted. Whisk egg yolks with 5 tbsp milk and stir into sauce.
Grease a large baking dish and spread a thin layer of sauce on the bottom. Cover sauce with one third of sliced potatoes, then half the spinach. Repeat, ending with a topping of sauce. Sprinkle with the rest of the cheese and the pine nuts and bake for 45 mins until golden brown.