Recipe adapted from smitten kitchen
This is so yummy, however I must warn that it is definitely not a quick meal to prepare. To save time you could prep your greens and do your measuring, chopping and slicing the day before; that way the following day all you will have to do is cook your roux, assemble and bake!
1/2 stick butter
1 large cooking onion, diced
2 large bunches of red chard, stemmed and chopped
2 cups organic 2% or whole milk,
2 large cloves of garlic, minced
2 tbsp flour
2 small zucchini, sliced into 1/8 inch thick rounds
4 medium russet potatoes, sliced into 1/8 inch thick rounds
1 tbsp fresh parsley, minced
1 tbsp fresh thyme, minced
salt and pepper to taste
1 1/4 cup grated cheese of choice, I used a mix of cheddar, mozzarella and parmesan
Onions and Chard:
in a large pan cook onions with 2 tbsp of butter over medium-low heat until softened (making sure to stir often) about 5 minutes. Turn heat to medium-high and add the rainbow chard. Stir until the chard is wilted. Add salt and pepper to taste. Transfer to a collander and using a dish towel press down on the chard to remove andy excess liquid.
In a small saucepan combine the milk and garlic; bring mixture to a simmer to keep it warm. In a medium saucepan melt 2 tbsp of butter over medium heat and whisk in the flour. Continue cooking the roux by whisking for one minute then while you continue to whisk slowly add the warm milk and garlic and bring to a boil. Whisk for about 1 minute more then season with salt and pepper. set aside.
Preheat the oven to 400. grease a 9×13 baking dish. Spread out half of the potatoes and half of the zucchini. Sprinkle with salt and pepper, 1/4 of the herbs and 1/4 cup of cheese. Spread half of your chard over the cheese, then sprinkle with salt and pepper, 1/4 of the herbs and a 1/4 cup of the cheese. Pour half of the roux over these layers then continue with the remaining potatoe and zucchini, salt and pepper, 1/4 of the herbs and 1/4 cup of cheese. Now top with the last of the chard. Sprinkle with salt and pepper. Pour the remaining sauce over the gratin, making sure it is as evenly distributed as possible. Finally top it off with the last of the cheese.
Bake for 40 minutes to 1hr or until golden and bubbly. Let stand for 10 minutes and serve!