In a large pot, cook pasta in lightly salted water according to the instructions on the package. The last 4 minutes, add broccoli and cauliflower florets too.
In same pot, make bechamel sauce. Melt butter (or ghee) in small saucepan or skillet. Add flour and whisk until lightly browned. Gently add milk while stirring constantly. Then add the cheese, keep stirring until thickened. Add black pepper, salt, nutmeg, and a squeeze of lime or lemon to finish.
Preheat oven to 400°F or 200°C.
When ready add drained pasta, veggie mix and chives to the becahmel sauce. Mix well.
Add to oven dish and top with mozzarella cheese. You could use a bit less cheese and add panko or breadcrumbs instead.
Cook for 10 to 15 min. If not nicely browned grill for last few minutes.