You'll want to first layout the "Base" font, and color it. Once everything's in place, duplicate the text box (place it on a new layer for easier control), change it to the "Letter" font, and change the color. As long as the text boxes stay aligned, you should get a good effect.
If you want to change the text to something different, I recommend using ‘Find and Replace’ so you can do it once for both layers.
Visto per la prima volta su DaFont: 23/07/2017