- Preheat the oven to 375 degrees. Grease a 9x13-inch baking dish with cooking spray.
- Bring a large pot of salted water to a boil.
- In a large saucepan, melt butter over medium heat. Once melted, add garlic and saute until fragrant, about 1 minute. Add flour and whisk until combined and golden in color. Slowly add in milk, then chicken broth, whisking until combined. Add in lemon juice and season with salt and pepper. Increase heat, whisking constantly, until sauce begins to thicken. Stir in parmesan cheese and continue to cook over medium heat until cheese is melted. Remove from heat and set aside.
- Add noodles to boiling water and cook according to package directions until al dente. Once cooked, drain and rinse under cold water, separating them to ensure they don't stick together.
- In a medium bowl, whisk together ricotta, egg, salt, and pepper.
- To assemble, ladle and spread 1 cup of sauce into the bottom of prepared dish. Remove 1 cup of the remaining sauce and set off to the side, then add chicken to remaining larger portion of sauce. Place 3 lasagna noodles over sauce vertically, then 1 cut piece horizontally. Spread 1/2 of chicken in sauce over the noodles, then top with 1/2 of broccoli. Sprinkle with 1/3 of the mozzarella, followed by 1/2 of the ricotta, followed by 1/3 of the parmesan. Top with 3 more noodles vertically and 1 cut piece horizontally, then the remaining chicken in sauce, then the remaining broccoli. Sprinkle with 1/2 of remaining mozzarella, the rest of the ricotta, then 1/2 of the parmesan. Top with another layer of noodles, then reserved cup of sauce. Sprinkle with remaining mozzarella and parmesan.
- Lightly tent with foil and bake for 35 minutes. Uncover and continue baking for 10-15 minutes until cheese is golden and bubbling.
- Allow to cool for 10-15 minutes before serving.
Prep Time: 20 minutes
Cook Time: 1 hour 5 minutes
Total Time: 1 hour 25 minutes
For the cooked chicken, leftover shredded chicken works great, but I prefer to brown chicken breasts in a pan with some salt and pepper until they're cooked through, then cut them into very small bite-sized pieces. Either works but browning them adds some extra flavor!
For the lasagna noodles, it would work to just use 9 noodles (3 layers of 3 vertically), but I like to position the 3 vertical noodles all the way to one end, then cut one noodle so that it fits horizontally at the other end, ensuring there are no noodle-less spots.
If you happen to end up with less than enough mozzarella to cover the top fully, I definitely recommend adding a bit more for a perfectly cheesy top!