Cauli & Sage Risotto with Walnuts using a slow cooker - or not!

This is a dish that can be cooked on the hob, in the oven, or in the slow cooker; here is my slow cooker version, with notes on the other methods at the end. The recipe was inspired by an oven-bake version from Sainsbury's Magazine March 2017.

The resulting quantity would serve 4, and this method needs about 1h 40m from start to serving. The cooker comes on right at the start (I keep it on high setting throughout for this), and the cauliflower and following ingredients can be prepared while the onion etc is cooking.

Cauliflower and Sage Risotto with Walnuts

This is about half the complete recipe

Ingredients
30g butter
1 large onion, peeled and chopped fairly finely
3 good garlic cloves, peeled and crushed or pressed
150g risotto rice
450ml hot vegetarian stock
1 medium cauliflower, florets only, cut to ping-pong-ball size
leaves from 1 large stem of sage, finely snipped (8-10g)
50g walnut pieces, coarsely chopped
60g crumbled vegetarian cheese (I use 40g hard/Cheddar, 20g blue)

Method
1  Start the slow cooker on high, adding half of the butter and leave to melt while
          preparing the onion and garlic.

2  Add the onion, garlic and rice to the cooker, stir well, then leave for 5 mins.

3  Pour in about 400ml of the stock, keeping the rest in case needed later.
          Stir then leave for 45 mins. If the mixture starts to look claggy, stir in
          more stock bit by bit.

4  Meanwhile, prepare the cauliflower, sage, walnuts and cheese. Bring water to
          boil in a large pan then simmer the cauli florets for 5 mins. Drain the
          water from the pan, add the remaining butter and sautee the cauli very
          gently for another 5 mins. (I prefer this to adding it early on to the cooker
          as it gives better control of consistency.)

5  Optional - dry fry the walnut pieces for 3-4 mins. (Put in small dry pan over 
          medium heat and stir often, avoiding burning.)

6  After the 45 mins, add in the cauliflower, sage and walnut pieces, mix well
          and cook for 15 mins.

7  Then stir in the cheese and leave to cook for a further 10 mins.

     *                    *                    *                    *                    *                    *

To bake this in the oven, I'd suggest 160C. 
(a)  Sautee the onion and garlic in a pan.
(b)  Mix in the rice and stir for a minute or two.
(c)  Add the stock.
(d)  Pile into a large oven dish (leaving enough space for the cauliflower.) 
(e)  After about 30 mins add the cauli, sage, walnuts and cheese, mixing well.
(f)  Bake for a further 20 mins.
For more excitement, top with some grated cheddar for the last 10 mins!

For cooking on the hob, use a large pan. Follow (a) to (c) then (e), adding a little extra stock if needed as it cooks. Stir from time to time. Cook for a further 15-20 mins until you like the consistency.

No side dishes are necessary here, although some warm, crusty garlic bread would be great if that's not too much carb. Otherwise a side salad.

Substitutions
Broccoli, broad beans, peas all go well in this risotto. Instead of walnuts: hazelnuts, brazils or pecans would be good; almonds might stay rather too hard. Thyme leaves instead of sage? This recipe should be called 'Anything with Anything Risotto'.