Creating Asparagus Au Gratin is a straightforward process. Follow these steps for a delightful outcome:

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Prepare Asparagus: Blanch the asparagus in boiling water for 2-3 minutes until bright green. Drain and rinse under cold water to stop the cooking process.
3. Make the Sauce: In a saucepan, melt the butter over medium heat. Add the flour, stirring for about 1 minute until it forms a paste. Gradually add milk, whisking continuously until the mixture thickens.
4. Add Cheese: Remove the pan from heat and stir in the cheddar and Parmesan cheese until melted. Add salt, pepper, garlic powder, and onion powder. Mix well.
5. Combine Ingredients: In a baking dish, layer the blanched asparagus and pour the cheese sauce over the top, making sure the asparagus is well-coated.
6. Add Breadcrumbs (Optional): If desired, sprinkle breadcrumbs on top for an extra crunchy layer.
7. Bake: Bake in the preheated oven for 25-30 minutes or until the top is bubbling and golden brown.

Follow these instructions carefully to create a dish that is both delicious and a feast for the eyes.