Ham, Swiss and Broccoli Roll ups in Basil Cream Sauce

I've made this recipe for so long I honestly can't remember where I got it.  I used to say it was my favorite of all the dishes I make.  I love the combination of the creamy basil sauce with the ham, Swiss and broccoli. Serve it over rice.
Ham, Swiss and Broccoli Roll-ups in Basil Cream Sauce
12 slices deli ham (I like Black Forest, but any kind will do)
12 slices Swiss Cheese
Broccoli spears (12 nice ones)
1 onion, chopped
4 Tablespoons butter
4 Tablespoons flour
1 teaspoon salt
1/2 teaspoon dried basil or about 10 leaves fresh, chopped fine
2 cups milk

Put the broccoli in a saucepan with water and salt and bring to a full boil.  Turn off the heat and put the lid on and let the broccoli steam while you prepare the sauce.
Saute the onion in the butter until the onion is soft.  Add the flour and cook and stir for a few minutes.  Add the milk and whisk until smooth.  Add the salt and basil.  Stir and cook until thickened.  Remove from heat.
Assembly:
Spray a 9x13 pan.  Lay out a piece of ham and put a slice of cheese on it.  Put a broccoli spear in the center and roll the ham and cheese around the broccoli.  Put seam side down in the pan and repeat for the rest of the ham and cheese.  Pour the white sauce over all (I always strain the leftover broccoli bits and put them in the sauce) and bake in a 350 oven until it's hot and bubbly and the cheese is melted.   Serve over hot rice.