This is cozy up comfort food served along side mashed potatoes. It has been raining for three days straight now, we are back to "monsoon" weather.  On days like this, comfort food is what I look for....
For this dish, I used dried rub sage - if you have fresh all the better!  This dish would also be lovely with Asparagus.
2 cups of diced ham
1 large leek, sliced in half and chopped
Olive oil
4 cups of roughly chopped green cabbage
Bechamel sauce:
2 - 3 cups of milk (I used soy milk, and actually forgot to measure - so go by consistency)
3 Tblsp. butter
1 large minced shallot
2 large garlic cloves finely minced
1 rounded tsp. Dried Rubbed Sage
salt and pepper to taste
Cornstarch, to make a slurry with some extra milk
about 2/3 of a cup Parmesan Cheese
For the top of the gratin:
extra sprinkling of Parmesan Cheese
Grated Aged Cheddar Cheese
Begin by shredding the cabbage, placing into a medium sized sauce pan and add water, not quite to cover.  Bring to a boil, lid on, then reduce to a low simmer cooking until tender.  Once cooked, mine took about 12-15 minutes,  line a colander with a clean tea towel and drain the cabbage, then set aside.  After 10 minutes, transfer the drained cabbage to a bowl.
In another saucepan, on low medium heat, add in the butter to melt.  Then add in the shallot and garlic, sauteing to sweat out.  Season with salt, pepper, and dried rubbed Sage.  Pour in the milk and bring to a simmer.  I make a cornstarch slurry to thicken, to  make the consistency of the sauce quite thick.
Once the sauce is thickened, remove from the heat, and stir in the 2/3 cup of Parmesan cheese to melt.
Pre heat the oven to 350 degrees.
Heat up a frying pan on medium heat, with a good drizzle of olive oil.  To the pan, add the sliced leeks, and diced ham.  Saute about 10 minutes, or until the leeks are tender.
Transfer the drained cabbage, the cooked leeks and ham to the Bechamel sauce, stirring to combine.  Then transfer the mixture to a lightly greased casserole dish.

To the top, add a light sprinkling of Parmesan cheese, then cover generously with grated aged cheddar cheese.  Bake for 30 minutes, then remove the foil and turn the heat up to broil, to lightly brown the cheese.  With my strange oven, this took about 5 minutes - just watch so it does not burn.
Serve along side mashed potatoes or cooked rice.