Gratin of scallops in lemon sauce

We have a lemon tree ... yes a lemon tree and we live in Belgium. So far nothing suprising. However, this tree is producing fruits! For me to see a lemon tree with fruits in Belgium, which is not known for its friendly climate, was a shock ... a positive one, of course. I have been thinking how to use these "made-in-Belgium" lemons and I ended up thinking of this scallops gratin. Something light, fresh, summery (even if it feel yet like winter here) and, most importantly, delicious!
Before we dive in the recipe, what is my comment on the lemon fruit? Great, tangy, wonderful scent and aroma ... let's hope it will live long!!

Serves: 4 as main course or 8 as a starter
FlexiPoints: 6.5 or 3.2

Suggested wine: Falanghina

Ingredients:
- 16 large scallops (meat only)
- 50g flour
- 50g butter
- 500ml full-fat milk
- 1 large lemon
- Salt as needed

How-to:

1. Melt the butter in a pan with a thick base. Avoid it to burn. Stir in the milk. Once the mixture is hot (but not boiling), reduce the heat. Stir in the flour through a sieve one spoon at a time. Continue stirring until a smooth white sauce is obtained.
2. Grate the zest from the lemon and add it to the white sauce. Stir well and let cool down.
3. Roughly chop the scallops in big pieces and season with salt.
4. Once the lemon sauce has cooled to room temperature, add the scallops and mix gently. Distribute among four flat oven-proof dishes.
5. Finish under the grill until the sauce is bubbling and has taken a brown colour. Serve immediately.