Tarragon Chicken Gratin with Lemon

Another lovely way of making a second hot meal from a roast chicken. I reckon you need at least 300g of chicken to feed two generously in this instance because there is only onion and tarragon in the creamy sauce, no other veg to baulk it out. The top has a thick breadcrumb and Parmesan cheese covering that ends up in delicious crisp contrast to the creamy, aniseedy sauce that holds the chicken. Unbelievably good.

Serves 2, generously
Prep: 20 min
Cook: 45 min

1 large onion
1 tbsp olive oil
40g butter
300g roast chicken
8g bunch tarragon
4 tbsp coarse breadcrumbs
3 tbsp grated Parmesan
100ml chicken stock
1 tbsp flour
100ml white wine
200ml milk     

Halve, peel and finely chop the onion. Melt 15g butter in 1 tbsp olive oil in a spacious, lidded frying pan over a medium heat. Cook briskly, stirring often for a few minutes, add a generous pinch salt, reduce the heat, cover the pan and cook gently, stirring occasionally, for about 15 minutes while you prepare everything else. Tear or cut the chicken into bite-size pieces, discarding skin, gristle etc. Strip the tarragon from its stalks and chop. Mix together the breadcrumbs and Parmesan on a plate. Now back to the onions. You want them slippery soft and adding liquid can help this, so add the stock and stir constantly as it bubbles away. Add remaining butter and when melted, sift the flour over the top. Stir vigorously until disappeared then add the wine and tarragon. Stir as it makes a thick roux and add the milk, adjusting the heat and stirring constantly to make a rich, creamy sauce. Simmer for 5 minutes, taste and adjust the seasoning with salt, pepper and squeeze of lemon. When satisfied with the balance of flavours, fold in the chicken. Tip into a 5cm gratin dish (approx 1 ½ litre capacity), allow to cool then scatter the crumbs over the top. Place on a roasting sheet in case of spillage and bake at 200C/gas mark 6 for approx 30 minutes, checking after 20. You want the top crusty and golden, so your fork cracks through the carapace onto a creamy, luscious filling.