Preheat your oven to 400°F. While it heats, trim the asparagus and cut into 2-inch pieces, mince the garlic, finely chop the chives into 1/8-inch pieces, and zest the lemon. Combine the cheddar and mozzarella in a bowl—I like to mix them together first so they're evenly distributed during layering. This prep work ensures everything is ready before you start building the casserole.

In a large bowl, toss the cut asparagus with olive oil, minced garlic, salt, pepper, and red pepper flakes until evenly coated. In a 9x13 inch baking dish, create three even layers: start with 1/3 of the seasoned asparagus, then sprinkle 1/3 of the combined cheeses over it. Repeat this layering process two more times, finishing with cheese on top. I like to pack the asparagus gently as I layer—this helps it cook evenly and creates a cohesive casserole rather than a loose mixture.

Place the layered casserole in the preheated 400°F oven and bake for 15 minutes, until the asparagus is tender when pierced with a fork and the cheese is melted and beginning to bubble at the edges. While the casserole bakes, prepare the hollandaise sauce according to your preferred method (this is a good use of your cooking time).

Remove the casserole from the oven. Drizzle the warm hollandaise sauce evenly over the top, then sprinkle with the finely chopped chives and lemon zest. The heat from the casserole will gently warm the hollandaise and release the fresh aromas of the chives and citrus, creating a bright finish to this rich dish.