In a large skillet, over medium-high heat, add bacon. Cook until brown and crispy, about 6-8 minutes. Transfer to a plate, lined with a paper towel; set aside
Melt butter in a large stockpot, add garlic, onion, carrots and celery. Cook, stirring occasionally, until tender. Whisk in flour until lightly browned; gradually whisk in chicken broth and milk. Cook, whisking constantly, until slightly thickened. Stir in cauliflower and bay leaf.
Bring to a boil; reduce heat and simmer until cauliflower is tender, about 12-15 minutes. Season with salt and pepper, to taste. If the chowder is too thick, add more milk as needed until desired consistency is reached. Serve immediately.