- Place cauliflower florets in a steamer basket over boiling water,cover and steam until tender, 8 to 10 minutes. (Alternatively, place florets in a microwave-safe bowl with 1/4 cup water, cover and microwave on High for 2 to 4 minutes.)
- Meanwhile, whisk flour with 2 tablespoons milk until smooth.
- Heat the remaining milk in a saucepan over medium heat until steaming.
- Add the flour mixture; cook, whisking, until the sauce bubbles and thickens, 2 to 3 minutes.
- Remove from heat; stir in Gruyere, chives (or parsley), garlic, salt and pepper.
- Spoon over the cauliflower and serve.