In a large enameled dutch oven or soup pot, cook the bacon over medium heat, stirring occasionally, until crisp,10-15 minutes.
Once crisp, remove bacon to a paper towel lined plate, and reserve bacon fat in pan. Reduce heat to medium-low.
Add butter and melt.
Add scallion whites, carrots, and celery, and season with salt and pepper. Cook 5-6 minutes, stirring occasionally, until tender.
Add garlic, thyme leaves, smoked paprika and onion powder. Cook stirring occasionally until fragrant, 1 minute.
Add flour, and whisk well until fully incorporated.
Whisk in beer, and stir until well combined with flour and veggie mixture.
Add the chicken stock, Worcestershire sauce, dijon mustard and cream to the pot, and stir well.
Turn heat to high and bring to a boil.
Once boiling, reduce heat to low, and simmer for 5 minutes.
Stir in fontina, cheddar and parmesan cheeses until just melted.
Serve with additional shredded cheese, reserved bacon, and sliced scallion greens.