Clean and chop all vegetables, garlic and grate cheese.In a large pot melt butter over medium high heat. Add onion and celery and cook until becoming translucent (about 5-6 minutes). Add garlic and cook another 1-2 minutes.Add chicken broth and broccoli. Cover and cook until broccoli is tender (about 10-12 minutes).While #3 is cooking, in a large mixing bowl, add milk and then slowly add flour while whisking well to combine completely.When broccoli is tender slowly add the milk/flour mixture to the pot while stirring slowly. Continue to stir slowly until thickened (4-5 minutes).Now add salt, pepper, and bacon (optional) along with the cheddar while still stirring. Simmer for 5 more minutes and serve.