What to do with leftover thawed breast milk

CL

I’ve been making my daughter porridge with my frozen breast milk.

I only need a couple ounces though but I have loads of 3.5 plus ounces in the freezer and it only lasts for 24 hours defrosted in the fridge.

I don’t want to use a whole 4oz bag either for porridge as I will have to add even more oats and waste milk & oats.

Any ideas, tips???