You could add lots of chopped parsley or oregano or basil or chives to the dish as you're assembling it, before baking. You could use other vegetables. I imagine diced winter squash instead of the potatoes would be fabulous and very pretty. Sausage, bacon or any kind of leftover meat would be good. You can vary the cheeses, omit entirely, and so on and so forth!
- 4 Tablespoons butter
- 4 Tablespoons flour
- generous 2 cups of whole milk (2% can work in a pinch)
- bay leaf
- 1/2 teaspoon chili flakes
- 1 teaspoon Dijon-style mustard
- pinch of ground nutmeg or cloves
- fresh minced thyme, parsley, chives, etc. (optional)
For the gratin:
- 3-5 potatoes (depending on size) and cut into thumb-sized chunks
- 1/2 medium to large green cabbage (or a whole small one), cored and cut into 1-inch pieces
- Handful or two of small pasta (optional)
- Bread crumbs (optional)
- Grated cheese (sharp cheddar, Gruyère, Emmentaler, . . .)
Melt butter in a medium-sized saucepan over med/low heat. When melted, whisk in flour. Continue cooking the roux for 2 -3 min, whisking frequently. Meanwhile heat milk until it's scalding. Whisk hot milk into roux and add several pinches of salt, grind in some pepper, add chili flakes (or omit if you'd like), add mustard and a bay leaf and a grating or two of nutmeg. Stir well and cook over med/low heat for about 10 minutes until thickened and bubbling. Add some grated cheese (sharp cheddar, Gruyère, Emmentaler, etc. ) and fresh, chopped herbs if you'd like at this point.
Put potatoes in a large pot with lots of water and two teaspoons of kosher salt. Bring to a boil. If you are using some kind of pasta you'll want to add it to the potatoes just a few minutes after the water comes to a boil so the pasta can cook for 8 or so minutes (depending on the type you choose this will vary. The pasta can be quite all dente when you drain everything though since it will keep cooking in the oven.) When the potatoes (and pasta, if using) are almost tender add the cabbage to the pot. Cover and cook for another few minutes until the cabbage is tender. Drain.
Spread the vegetables in a large baking dish. Pour the béchamel over the top and mix in a bit. Sprinkle with breadcrumbs and extra cheese (if you'd like) and bake at 400 until bubbly and crisp on top (I broil it at the end for a few minutes).