Starting to Bulk cook - Sweet and sour Beef Stew

I have been inspired by a friend to start cooking batch meals. So instead of making 1 meal at a time, I will be trying to make 3 or 4, and freeze the rest to make life easier cooking wise. Of course this also saves on dirty pots and pans and electricity to cook the food.
My helpers - I had laid out all the vegetables the night before that I needed to make the Sweet and Sour Beef stew. When the children woke up I asked them if they would help prepare the vegetables. Well after their breakfast Jude washed the vegetables, and Eden and Niamh peeled and chopped them(except for the onions). What a lovely surprise to come downstairs and see them nearly finished, and what a big help.
And all put in the slow cooker for the day, this is about 4 meals worth + this type of thing is Michael's favourite food.

Recipe: (I have not added vegetables to the recipe, just use whatever you have)

425g can of pineapple chunks in syrup
30ml oil
700g lean stewing steak cut into cubes
1 onion, chopped
2 celery sticks
30ml cornflour
300ml beef stock
30ml soy sauce
30ml ketchup
45ml wine vinegar
Salt and freshly ground black pepper

Drain the pineapple and reserve. Make the juice up to 450ml with water.
Heat the oil in a frying pan and quickly brown the meat. Transfer to big pot/slo cooker/pressure cooker.
Add the onion and celery to the pan and cook for about 5 minutes until just golden brown.
Stir in the cornflour, then gradually stir in the stock and reserved pineapple juice, except the pineapple. Bring just to the boil and pour over the beef.
Cover and cook until meat is cooked and tender. Add the pineapple for the final 30 minutes.