Step 3: Simmer and Thicken
Reduce heat to medium-low and simmer, whisking often to prevent scorching.
Step 4: Add the Cheeses
Once thickened, stir in Parmesan and Pepper Jack until the sauce is glossy and smooth.
Step 5: Assemble and Bake
Pour the sauce over the middle of the asparagus stalks, leaving the tips exposed. Sprinkle extra mozzarella and red pepper flakes if desired. Bake for 15 minutes. (Check at 12–13 minutes if you like slightly firmer asparagus.)
Step 6: Finish with Bacon
Remove from oven, sprinkle crumbled bacon on top, and bake 3 more minutes to warm the bacon. Serve immediately.
