1: Cut 400 g chicken breast into medium-sized chunks.
2: Pour 3 tablespoons olive oil into a large frying pan on high heat. When good and hot, add the chicken, salt and pepper. Fry until lightly browned all over.
3: Turn off the heat, then add 2 tablespoons chilli spices and mix well to coat the chicken evenly with the spices.
6: Melt 50 g butter in a large frying pan on high heat. When good and hot add enough fresh spinach all at once to fill the pan. Be careful: the water left on the leaves will spit at first, so take care not to get scalded.
7: Stir with a spatula until the spinach has shrunk down. as shown in the photo. You have just "wilted" the spinach in butter – another cooking method. Wilt all the spinach like this in batches, transferring it to a plate when done.
8: Preheat the oven to 410°F (210°C). Butter a gratin dish and spread half the spinach in the bottom. Salt and pepper.
9: Add the chicken pieces.
10: Spread half the bechamel sauce on top.
11: Add the rest of the spinach; salt and pepper again.
12: Finish with the remaining sauce and scatter grated cheese over the top.
13: Bake for about 40 minutes until the top is nicely browned. Your gratin is ready.
Remarks
You can replace the béchamel sauce with a Mornay sauce. If you're using cooked spinach rather than fresh, omit steps 5 to 7.