Clean the cauliflower and divide it into florets, cut the stem into small cubes. Bring a pot of water to a boil, add some salt and the cauliflower. Bring to a boil again and cook the cauliflower for 5 minutes or until al dente. Drain but reserve the cooking liquid. Measure 500 ml/ 2 ¼ cups of it in a jug. Stir in the stock powder or cube while the cooking water is still hot.

In a large bowl mix together the turkey ground meat, finely grated potato, breadcrumbs, mustard, finely chopped onion, grated garlic cloves, finely chopped parsley, thyme, and sage, lightly beaten egg, 1 teaspoon salt, and some pepper. Form about 20 meatballs, about the size of a golf ball.

Heat the oil in a non-stick or cast-iron pan and brown the meatballs on all sides, working in batches. It should take about 10 minutes per batch. They should be nicely browned and almost cooked through. They will finish cooking in the oven.

In the meantime preheat the oven to 180 degrees Celsius/ 350 degrees Fahrenheit and make the white sauce.

Chop the onion very finely. Melt the butter in a saucepan and cook the onion until golden. Sprinkle the flour on top and stir for a couple of minutes until the flour starts getting a bit golden as well.

Slowly start pouring the reserved cooking water while whisking continuously. Bring to a simmer and let cook for about 3-4 minutes while stirring very often. Add the cheese and let melt in the sauce. Taste and adjust with salt and pepper.

Lightly butter a casserole dish. Mix the cauliflower, turkey meatballs, and sauce together and add them to the prepared dish. You can top the casserole with more cheese if you wish, I didn't.

Bake for about 20-30 minutes or until golden brown. Sprinkle with parsley and serve with salad.