Cook the noodles.
Boil lasagna noodles in salted water until just under al dente (they’ll finish cooking in the oven). Drain and lay them flat on a baking sheet lined with parchment or a bit of oil so they don’t stick.

Make the filling.
In a bowl, mix the shredded chicken, pesto, ricotta, egg, ½ cup mozzarella, ¼ cup Parmesan, and a pinch of salt and pepper. Stir until creamy and well combined.

Whip up that sauce.
In a saucepan over medium heat, melt the butter and whisk in the flour. Cook for 1 minute, then slowly add the milk while whisking constantly. Stir in the garlic, season with salt and pepper, and let it simmer for 3–4 minutes until thickened. Take it off the heat and stir in the remaining Parmesan.

Assemble the roll ups.
Spread a thin layer of sauce in the bottom of a 9×13-inch baking dish. Take each noodle and spread a generous amount of the chicken pesto filling across it, then roll it up (like a cinnamon roll, but savory). Place each roll seam-side down in the dish.

Top it off.
Pour the remaining white sauce over the roll ups, sprinkle with the rest of the mozzarella, and an extra spoonful of pesto if you’re feeling wild.

Bake until bubbly.
Cover with foil and bake at 375°F (190°C) for 20 minutes. Remove foil and bake another 10–15 minutes until the cheese is golden and bubbly. Let rest for 5–10 minutes before serving (this helps everything set and avoids lasagna soup).