{
    name: "Glenfiddich 15",
    notes: [
        {
            user_name: "Derick",
            date: ISODate("2013-10-02"),
            note: "Caramel and honey, fruity with some hints of earth",
            likes: 17, rating: 3,
        }
    ]
}
<?php
$whisky 
= new (\MongoDB\Client)->demo->whisky;

$newReview = [
    
user_name => "Michael",
    
date => new \MongoDB\BSON\UTCDateTime( new DateTimeImmutable("2017-02-02") ),
    
note => "No peat, but fruity",
    
rating => 1,
];

$whisky->updateOne(
    [ 
'name' => 'Glenfiddich 15' ],
    [ 
'$push => [ 'notes' => $newReview ] ]
);
?>