Preheat oven to 190˚C. Cook lasagna sheets in a large pot of water then drain hot water and add cold water to the pot to stop the cooking process and prevent noodles from sticking together. Shred 4 cups of boiled chicken.

Place a pot or large saucepan over medium heat, add 2 Tbsp olive oil and saute onions for 3-4 minutes or until softened. Add 4 Tbsp butter and whisk in 1/3 cup flour. Continue whisking 3 minutes or until flour mixture is golden. Add chicken stock, milk and pepper powder. Add minced garlic and chopped spinach, and stir to combine then remove from heat

Spread the spinach bechamel at the bottom of a casserole dish. Add 3 lasagna sheets. Then add shredded chicken. Pour spinach sauce, red olive red pasta sauce and spread and add cheddar cheese.

Then repeat the same layers and finally add mozarella cheese. Place in oven for 30 minutes. Arrange 10-12 toothpicks over the top to keep the foil from touching the cheese then cover with a large sheet of foil. Take out from oven and cool down before serving.