1c almond or cashew milk (but I'm sure whatever milk sub you drink would work)
1 5oz container Greek yogurt or 1/2 to 3/4c coconut milk ice cream (brand is so delicious- make sure it's the no sugar added line! I use vanilla)
A splash sf vanilla torani or davinci syrup
A slightly rounded tsp matcha
A handful of ice
A little vanilla extract if I have the fancy kind on hand

It's a flexible recipe- just take it easy on matcha. A little goes a long way, and too much makes it quite grassy. You should add it but by bit, tasting along way to find right amount for your wife.
It's so nice of you to recreate her old favorite!