cauliflower hash brown casserole

I was sure I'd posted a version of this recipe before but I checked and it doesn't appear that I have. Hash brown casserole is something I do fairly regularly. I keep a bag of the diced hash browns in my freezer for times when I'm lacking ideas and the other day, I had a head of cauliflower and some ham so this is what I made for dinner.

Cauliflower Hash Brown casserole ( a mummydinosaur original)
1 head of cauliflower, cut into florets or small slices
olive oil
3 tbsp butter
3 tbsp flour
250 mL milk
250 mL vegetable stock
1 tsp dijon mustard
1 c grated smoked cheddar
1 c diced ham (I did big chunks)
500 g of diced frozen hash brown potatoes

Roast the cauliflower with a dash of olive oil for about 20 minutes in a 400 deg F oven, or until the cauliflower is tender and brown in spots.

Meanwhile, melt the butter over medium heat. Add the flour, milk and vegetable stock and stir or whisk well until smooth. Let the mixture come to a boil, turn down the heat a bit and simmer for 5 minutes. Add the cheese and the mustard and stir until smooth.

In a greased casserole dish, add the frozen hash browns, the diced ham, the cooked cauliflower and add the cheese sauce and mix well. Bake at 350 deg F for 30 minutes or longer, until the casserole is bubbly around the edges.

This can be adapted for any other vegetable or combination of vegetables using ham or not, to your taste or based on what is on hand.