In a medium saucepan, melt butter over medium heat.
Whisk in flour and cook for 1 minute.
Gradually whisk in milk. Bring to a boil, whisking continuously.
Add cheese a handful at a time, stirring until smooth after each addition.
Stir in turkey, half of bacon, and half of green onion.
Transfer to a fondue pot
or slow cooker
to keep warm.
Sprinkle remaining bacon, green onion, and the tomato on top.