(Pasta) Pop on a large pot of water to boil- once boiling cook the pasta. Use the packet directions as a guide for cooking time, as the pasta will also be baked I tend to cook the pasta for approximately two-thirds of the suggested cooking time, but while this is happening you can move on to the other steps.
(Chicken) Heat a pan and brown your chicken
(Veggies) Cut the cauliflower into florets, add to a second pot, cover with water and bring to boil (leave to boil until tender)
(White Sauce ) Add butter to a third smaller pot, heat over a medium/low heat until melted
(White Sauce ) Heat your milk and stock (you don't have to, but the sauce making is much faster with warmed milk and stock)
(White Sauce ) Add the flour to the pot and cook off for the basis of your roux/white sauce
(White Sauce ) Gradually add the milk and stock to create a thick velvety sauce
(White Sauce )Add cheese to the white sauce and allow to melt into the sauce. Once done remove from the heat (you do not want a white sauce to boil, as it goes runny)
(Pasta) Remeber to check back on your pasta water and cook your pasta as per the packet instructions, once ready drain thoroughly
(Veggies) Remember to check on your cauliflower, once tender add 2 handfuls of spinach to the pot and let steam until wilted for a few minutes.
(Veggies) Drain the water from the cauliflower and spinach, blend to create a purée (I use a stick blender to do this)
Add the veggie purée to the cheese sauce and mix (do this in whichever is the bigger pot, ie the white sauce pot or the cauliflower pot. Be sure to taste the sauce at this stage, season with salt and pepper to your tastes.
Mix the sauce mixture and with the cooked pasta and browned chicken, add one more handful of spinach if desired and mix through
Pop the pasta mix into a baking/lasagna dish, top with grated cheese
Bake in an oven at 180 degrees for 30-35mins, until cheese, is melted and golden