все работает как часы =)
<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="utf-8">
</head>
<body>
<div class="mini-basket" style="display:inline-block; width: 100px; height: 100px; border: 1px solid grey;"></div>
<div class="mini-basket-layer" style="display: inline-block; width: 100px; height: 100px; border: 1px solid grey;"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
$('.mini-basket').on('mouseenter',function() {
$('.mini-basket-layer').css('visibility', 'visible');
});
$('.mini-basket').on('mouseleave',function() {
$('.mini-basket-layer').css('visibility', 'hidden');
});
</script>
</body>
</html>