01 -
Preheat oven to 180°C. Lightly grease a 23 x 33 cm baking dish with non-stick spray and set aside.
02 -
In a medium saucepan over medium-high heat, combine chicken broth and 60 ml milk. Bring to a gentle boil, then reduce heat to medium-low.
03 -
In a small bowl, whisk together flour, onion powder, garlic powder, black pepper, and salt. Gradually add the remaining 120 ml milk and whisk until smooth with no lumps.
04 -
Slowly pour the flour-milk mixture into the simmering broth, whisking constantly. Allow to simmer while stirring until the sauce is thick and smooth, about 5 minutes. Remove from heat and let cool for 10 minutes.
05 -
In a large bowl, combine cooked broccoli, sauce mixture, Greek yogurt, and chopped onion. Mix gently to blend. Transfer the mixture to the prepared baking dish, spreading evenly. Sprinkle with grated cheddar cheese.
06 -
Bake uncovered for 20 minutes or until casserole is bubbling and cheese is melted. Remove from oven and serve warm.