Heat a large sauce pan over medium to medium high heat. Add the butter to the pan, and next the cauliflower, shallots, and salt and pepper; cooking for 8 minutes. Add garlic, and cook an additional 1 minute. Sprinkle in the flour and stir into the veggies, it should look grainy, like wet sand. Slowly whisk in the broth a little at a time, stirring up the cooked bits on the bottom of the pan.