How do you log something you didn't buy or make? Calorie counting.

[overweightcat]

Every couple of weeks DHs brother makes some Homemamde pizza for us for dinner as a thank you for us doing his shopping (he's in the shielding group) - he makes the dough and everything from scratch and it's always 2 or 3 very thin 10" margherita pizzas for our family of 4 - we don't always finish them.

I've recently started calorie counting and sticking to 1200 a day in a bid to loose 2 stone using MFP and I don't know how to log it.
When I make my own recipes from scratch I sometimes use those nutrition and calorie calculator online to give me an idea but how can I log something I have no info on?

I usually have 2-3 slices (smaller and thinner than e.g. Aldi stone baked pizza cut into 8) with a few air fired chips and salad.

Does anyone have any idea how to log it?

I tend to search for that item and in the list of existing items look for one that seems about average. E.g. if you search margherita pizza, pick one that measures in slices and is about what you would expect.

If it's just 1 meal every couple of weeks that isn't completely accurate you should still lose weight

id look for a supermarket equivalent and log that, will be probably over guessing but safer imo