Place 350 grams cauliflower florets in a deep baking dish.
Drizzle over 1 tablespoon olive oil, then sprinkle on ¼ teaspoon fine sea salt, ¼ teaspoon ground black pepper, and ¼ teaspoon smoked paprika.
Rub the spices and oil into the cauliflower.
Roast for around 20 minutes, until the cauliflower is tender and has slightly caramelised edges. Continue with the rest of the recipe while it bakes.
Cook the Pasta
Bring a large saucepan of salted water to a rolling boil.
Add 140 grams penne pasta. Cover the pot and cook according to package directions. We're aiming for al dente.
Once the pasta is done, drain in a colander — but reserve the pasta water.
Make the Mustard and Cheddar Béchamel
Over low heat, melt 25 grams butter in a pan.
Add 25 grams plain flour (all-purpose flour) to the butter and stir in.
Cook out the flour, stirring now and then, until it changes colour and the aroma turns nutty.
Slowly add 300 millilitres full fat milk, stirring between each addition. Let the milk absorb into the roux before adding more milk, and stir constantly to avoid lumps.
Once all the milk is added, you should have a smooth, thick sauce. Next, add 1 ½ teaspoons French wholegrain mustard, ¼ teaspoon fine sea salt, ¼ teaspoon ground black pepper, and 1 small pinch ground nutmeg. Stir in and turn the stove off.
Grate 70-80 grams extra mature cheddar into the sauce and stir in. It should melt in the residual heat.
Bring it to Together
Add the cooked pasta and roasted cauliflower to your béchamel sauce.
If needed, add a few ladles of reserved pasta water to loosen things up.
Cook the Cauliflower Pasta Bake
Preheat your oven to 200℃ (392℉).
Tip the saucy pasta and cauliflower into a 6.5"x 9" baking dish1.
Grate over 20 grams extra mature cheddar.
Bake for 20 minutes, until golden brown and bubbly on top. Alternatively, you can grill/broil the top.
Notes
Extra mature cheddar is called extra sharp cheddar in the U.S. I use white cheddar. ¹ A slightly larger baking dish will do no harm; it may even prevent spillages!