Transform your Christmas lunch leftovers into an even more delicious sandwich, with Max Halley's ultimate food-waste-fighting festive sarnie. 

Recipe makes one sandwich, but of course, you can multiply it to make as many sarnies as there are of you.

Ingredients

For the patty:

• Leftover roast potatoes (about 4 or 5) or a heaped tablespoons of cooked veg (cabbage, carrots, peas, stuffing - whatever you have left over will work)
• 1 x egg, whisked up in a little bowl or ramekin
• For the slaw:
• Raw cabbage, sprout, onion, carrot and parsley (about 2 tablespoons' worth)
• Any vinegar or citrus-based dressing (1/3 lemon juice, 2/3 olive oil and a good pinch of salt whisked up together is absolutely perfect - but that lemon juice could be substituted with any vinegar you might have)

For the gravy and mustard mayonnaise:

• 2 heaped tablespoons of mayonnaise
• 4 tablespoons of gravy (however you make it at home)
• 1 teaspoon of your favourite mustard (I personally like Dijon, but feel free to sub out the mustard for any of your favourite condiments - but make sure not to switch out the gravy)
• Whatever leftover meat or meat alternative you have. Ham? Turkey? Both? Neither? All good!
• A cup of gravy on the side for dunking your sandwich in
• Whatever tasty crisps you might have lying about - my Mum always has those Tyrells Veg Crisps at Christmas
• 1 x English muffin (or perhaps a mini ciabatta or something similar - even toasted sliced bread works for sandwiches. All that matters is that there's crust everywhere and you don't even begin to consider using sourdough)

Method

For the patty:

1. Mash your roast potatoes, leftover veg and stuffing together with a fork or a potato masher and mash, mash, mash. (If I had a leftover pig in blanket, I'd mash it into this mix too just for the LOLS)
2. Add the beaten egg and mash, mash, mash again.
3. Season it up and form this into a small patty-like burger.
4. Refrigerate for at least half an hour. This will stop it falling apart when you fry it later.

For the slaw:

1. Slice 2 leftover sprouts and a few leaves of cabbage as finely as possible. Put them in a bowl and grate a small carrot in there too.
2. If you have a quarter of an onion or a spare shallot grate that in there too.
3. Mix up your dressing as described above and toss it through this lot.
4. Set the bowl aside to soften.

For the gravy mayonnaise:

1. Heat the four tablespoons of leftover gravy in a pan and boil until reduced by half. 
2. Beat it, hot, into the mayo. It'll look weird at first but keep beating, it will all come back together.
3. Set aside.

1. Put your leftover meat or meat alternative in the pan you heated the gravy up in for the mayo, add a splash of water and a touch of vinegar (whatever you've got) to the pan and heat it up.
2. Cut your muffin in two and toast the insides under the grill. Let it cool.
3. While it's cooling, fry the patty you prepared earlier in a medium hot frying pan in some hot vegetable oil. Do not be tempted to turn it too quick, let a crust build up and then flip it.
4. Heat some more leftover gravy up in a pan and keep it nice and warm.
   
   

1. Slather the insides of your muffin top and bottom with the gravy mayo.
2. Put a good heap of hot meat on the bottom.
3. Squish the bubble-esque patty on top of that.
4. Crush some crisps and sprinkle them all over the mayo'd inside top of the muffin.
5. Put the slaw/salad all over the patty.
6. Tip your extra gravy on to a little saucer or plate (warmed this in the oven first), to dunk your sandwich in.
7. Put the lid on the sandwich, give it a squish and GO GO GO.