Billy Boiler- thermal cooker

My partner’s parents bought us the best present ever! A Billy Boiler thermal cooker. Thermal cookers are a modern take on the old hay box cooker; they are a cooking pot with an insulating outer sleeve which keeps food hot and cooking for up to eight hours or so. I have wanted to try this for years now. Thanks to Mum and Dad I now have the chance.


The first night I made a fairly credible lentil/vegetable stew, made in the traditional way; by boiling green lentils, rinsing them then adding them to fried onion and garlic followed by any vegetable in the vicinity. It seems that thermal cooking is something I can do. The method in general is perfect for people with a short attention span as food is only on the stove for a matter of minutes before being plonked into the insulated outer sleeve and forgotten about until it is time to eat.

I thought I would share the basic method of using a thermal cooker by sharing a recipe that is becoming a favorite in our family;

Fake chicken pasta bake


1 large onion (chopped)

2 tablespoons vegetable oil


1 can tomatoes

1 can/ container cream

1 large zucchini (chopped)

approximately 1 kg Quorn fake chicken pieces

2 teaspoons chicken stock (we use the kind that doesn’t have chicken in it)


1 1/2 cups grated cheese


Fry the onion and garlic in the oil

Add the chopped zucchini and continue to fry, stirring often

Add the can of tomatoes and stir

Add the chicken stock and more garlic and stir

Add cream and stir in, if the mix does not look fairly liquid add half a cup of water

Let simmer for five minutes

Add pasta and stir through

Put lid on pot and place into the insulated sleeve, shut the lid and leave for 5-8 hours

When ready to serve, stir grated cheese through the mix until it is melted

Serve with fresh bread rolls


Onion and garlic frying


Zucchini added


Fake chicken added


Tomato added


Cream added. This is about how much liquid you should have at this point


Pasta added


Into the insulated sleeve it goes


Now I leave it to sit until I get hungry

The whole meal is cooked in the pot of the Billy Boiler (it saves so much washing up), the pot is big enough to feed four adults with hearty appetites. There are a few rules to remember when cooking in a thermal cooker. Always have the pot filled to at least 80% capacity, this ensures that the food inside can absorb enough heat to keep cooking for the full 5-8 hours. Always make sure there is a lot of liquid in the meals, liquid holds heat for longer than solids do. The most important rule of all is; don’t forget you already prepared a meal and start making dinner at 6.00pm (yes, I have done it), I find that leaving myself a little note on the kitchen counter helps me remember.

Thermal cooking is a great time saver, no more hanging over the stove for an hour, and it saves a lot of money on gas (or electricity if that’s what you use to cook with). We will save more energy in summer using thermal cooking because we use gas in summer but cook on the wood heater in winter, but the saving in time is the same all year. The fact that the food doesn’t burn, even though you have forgotten it’s very existence is a huge bonus to me.

If you would like to give thermal cooking a go you can start with a traditional wooden box filled with hay and see is you like it before spending money on a flashy thermal cooker unit. This handy recipe matrix has some great ideas for simple meals using the thermal cooking method.


It tastes delicious with extra cheese grated over the top

2 thoughts on “Billy Boiler- thermal cooker

  1. Excellent to hear there are stored-heat cookers now commercially available! I’ve been doing haybox cooking for years, and I love it. Not only does it use less fuel, but the rice or quinoa is always perfectly cooked, never burned on the bottom. Hopefully commercial models like this one will make stored-heat cooking more widely used.

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