WPF - Border template with content

Let's assume I have the following control template:

<ControlTemplate x:Key="Test">
    <Grid>
        <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="1" Width="33" Height="33" CornerRadius="3"/>
        <ContentControl Content="{TemplateBinding Property=ContentControl.Content}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
    </Grid>
</ControlTemplate>

How can I change content of the control in wpf? I've tried something like

<Control Template="{StaticResource Test}" BorderBrush="Black" Content="aa"></Control>

But when I do so I it says me that the property content is not recognized or it is not found.