Style XAML for Custom Control

What is the correct syntax for the style TargetType below if I have a custom entry control called "CustomEntry"?
I've tried a few different ways (example below), but it always throws an error about specified key not found.

<Application  xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            xmlns:rendered="clr-namespace:XXX.RenderedControls;assembly=XXX"
             x:Class="XXX.App">

...
<Style x:Key="baseEntryStyle" TargetType="x:Type rendered:CustomEntry">