Step 1
Cook asparagus in a saucepan of boiling water until bright green but still crisp about 2 minutes. Transfer asparagus to ice water to stop the cooking process. Drain and set aside.
Step 2
Melt butter in a saucepan over medium-low heat. Whisk in flour and stir until mixture becomes paste-like and light golden brown about 2 minutes.
Step 3
Whisk milk into butter-flour mixture; bring to a simmer and cook until thick 2 to 3 minutes. Season with salt and cayenne pepper.
Step 4
Place milk mixture garlic and asparagus in a blender and puree until smooth.
Step 5
Pour asparagus mixture into a large bowl; stir in egg yolks and Cheddar cheese.
Step 6
Preheat oven to 375 degrees F (190 degrees C)
Step 7
Generously butter 4 (6-ounce) ramekins
Step 8
Beat egg whites in a large glass or metal mixing bowl until soft peaks form. Lift your beater or whisk straight up: the egg whites will form soft mounds rather than a sharp peak
Step 9
Stir half of egg whites into asparagus cheese mixture until just combined. Gently fold remaining egg whites into mixture.
Step 9
Fill prepared ramekins about 3/4 full and place on a baking sheet; bake in the preheated oven until edges are golden brown about 20 to 25 minutes