Pesto White Sauce Chicken Lasagna 

3 tablespoons butter
3 tablespoons olive oil
1 small onion chopped (about 1 cup)
3 cloves garlic minced
2 teaspoons dried basil or 1 tablespoon fresh
1 teaspoon salt
1/2 teaspoon pepper
6 tablespoons flour
1/3 cup milk
1/3 cup Greek yogurt
1 and 2/3 cup chicken broth
2 cup cooked chicken chopped (rotisserie is best)
1 15- ounce container ricotta cheese
1/3 cup basil pesto homemade or store-bought
1 egg
9 lasagna noodles
1.5 cups mozzarella cheese
2-3 cups fresh spinach
3-4 tablespoons Parmesan cheese

Saute onion and garlic (add veggies if not using spinach)
Combine milk, yogurt, and chicken broth
Combine the basil, salt, pepper, and flour. Add to the onion mixture and whisk together until all the oil is absorbed.
Gradually add the milk mixture to the pan, whisking constantly. 
Cook over medium heat, stirring until the mixture is thickened slightly. 
Add the chicken and turn off the heat.
Combine ricotta, pesto, and egg.

Layers:
Thin layer of white sauce
3 noodles 
1/3 ricotta mixture
1/3 spinach, if using
1/3 white sauce
1/3 mozzarella 
Repeat twice
Sprinkle the top with Parmesan cheese