Thank you! Exactly what I wanted to try, but it did not modify the collection.

Am I doing it wrong?

    $purchases = $purchases->map(function ($purchase) {
        Debugbar::info($purchase->packaging->price);
        if ($purchase->packaging->price) {
            $purchase->packaging->price = (object) $purchase->packaging->price;
        }
        
        return $purchase;
    });

I use the following code to return an Eloquent ORM, including the latest price per item.

    $purchases = Purchase::with([
        'packaging',
        'packaging.item',
        'packaging.item.manufacturer',
        'packaging.item.brand',
        'packaging.unit',
        'packaging.price' => function ($query) use ($shopping_date) {

            $query->select(DB::raw('DISTINCT ON(packaging_id) *'))
                ->where('date', '<=', $shopping_date)
                ->orderBy('packaging_id', 'asc')
                ->orderBy('date', 'desc');
        }
    ])->where('shopping_id', '=', $id)->get();

Because of the raw DB, the resulting single 'price' object is returned as an array.

[ { key1: value1, key2: value2, ... packaging: { ... price: [ { ... } ] } }]

I have tried everything I could think of using pure Eloquent--latest() and latestOfMany()--but they all appear to find the latest before filtering by date.

I have written a JavaScript routine that traverse the returned collection and replaces the array of object with the object itself. But it does seem like the "clean" way to accomplish this.

Is there any way to return the price as a simple object or--at worst--some PHP code to clean up the 'purchases' collection before it is returned?