What is the intended way to make a label and text box side by side in WPF?

I'll often use this:

<StackPanel>
  <StackPanel Orientation="Horizontal">
    <Label>Username:</Label>
    <TextBox />
  </StackPanel>
  <StackPanel Orientation="Horizontal">
    <Label>Password:</Label>
    <PasswordBox />
  </StackPanel>
</StackPanel>

But it is such a common scenario, I feel like there is a way with less markup.

Also, is there a performance impact of using so many stack panels?