To make sure that your that chicken Béchamel is tasty all the way from the topping to the sauce to the innermost part of the meat, season the dish during every stage of cooking.
That means: 1) season the chicken ahead and leave overnight to marinate; 2) season the Béchamel sauce well; and 3) season the vegetables during sauteeing.
Why not just season after everything has been assembled in the pan prior to baking / broiling? By that time, it will be too late. Fifteen minutes in the oven is not enough time for the chicken to absorb the seasoning. And what it manages to absorb will detract from the flavor of the sauce. So, season every step of the way.
Okay, so, the chicken having been seasoned and having been left to aborb the flavors in the seasonings, we now give it texture and even more flavor. That means browning the chicken. Not cooking the chicken thighs through but just searing the surface.
Normally, I’d dredge the chicken in flour before browning BUT the chicken was going to be baked in Béchamel sauce which contains a lot of flour. Flouring the chicken might have turned the sauce too thick by the time the dish was cooked. So, no, I don’t recommend dredging the chicken in flour before browning.
The chicken having been browned, we do the sauce. I know the title says Béchamel sauce but adding vegetables won’t hurt. In fact, they add even more flavor, not to mention patterns and colors, to the dish. So as not to dilute the flavor of the sauce, the vegetables are cooked in butter with a bit of seasoning.
Now, it’s time to start assembling the dish. The Béchamel sauce is poured into the pan and the browned chicken thighs are arranged in a single layer. They will finish cooking in the sauce so they have to be arranged that way for even cooking in the oven. A second reason for arranging them in a single layer is so they get equal amounts of cheese. Yes, cheese.
When the chicken thighs are cooked through, the pan is taken out of the oven. Each chicken thigh is topped with a mound of shredded cheese before the dish goes back into the oven. With the top heat on (broiler mode), the cheese melts then gets toasted to form a light crust that adds more flavor, texture and color to the dish.
Marinate the chicken
- Wipe the chicken thighs dry with a kitchen towel.
- Place the chicken thighs in a bowl, add the lemon pepper seasoning and toss thoroughly.
- Transfer the chicken to a covered container and marinate in the fridge for at least 12 hours. Twice as long is even better.
Brown the chicken
- Preheat the oven to 375F.
- Heat the cooking oil in a pan.
- Brown the chicken thighs in hot oil, in batches if your frying pan is not very large, flipping them over for even coloring.
Assemble the chicken Bechamel
- In an oven-safe frying pan, melt the butter.
- Saute the onion until softened.
- Add the bell pepper and peas. Season with salt and pepper.
- Cook the vegetables for half a minute.
- Stir the Béchamel sauce into the vegetables.
- Arrange the browned chicken thighs on the Bechamel sauce.
Bake and broil the chicken Béchamel
- Bake at 375F for about 15 minutes or until the sauce is bubbly. The chicken should be cooked through at this point.
- Take the pan out of the oven.
- Turn up the heat to 400F and turn on the TOP heat.
- Place a mound of shredded cheese on top of each chicken.
- Put the chicken back in the oven and cook until the cheese is browned and lightly crisp.
- Optionally, sprinkle snipped greens (scallions or parsley) over the chicken Béchamel before serving.