Dissolve bouillon cube in hot water, add half-and-half.
In saucepan, melt butter and add flour. Whisk and cook mixture until frothy and
raw flour taste is gone. While stirring, add bouillon mixture. Stir constantly with
whisk until the sauce thickens and begins to bubble.
Add Swiss cheese and stir until smooth. (If sauce needs thinning, heat and add a little water.)
Assemble hot browns by placing turkey and onion on each bread slice.
Top with sauce and crumbled bacon.
Heat at 350 degrees F for 10 minutes, garnish with parsley.