Roasted Asparagus with Hollandaise Sauce

Asparagus are one of the veggies that I have discovered as an adult.  I would never have eaten them when I was younger and certainly would not have thought they were delicious.  But wow, how the years have changed me.  I really enjoy them roasted, I find them much nicer than boiled or steamed.  The white asparagus are largely aesthetics here, if you can't find them, just substitute for regular green asparagus.

1/2 lb (250g) thick green asparagus, with tough ends snapped off
1/2 l (250g) white asparagus, with tough ends snapped off
2 tbsp olive oil
salt and freshly ground pepper
1/4 cup unsalted butter
2 egg yolks
2 tsp lemon juice

1. Preheat oven to 425F.
2. (the recipe calls for peeling the asparagus stalks - I did not do this) toss with olive oil, salt and pepper.  Place on baking sheet.  Place in oven and bake for 10 minutes, turning once, or until stalks are crisp tender.
3. Heat butter in small pot until foaming.  Place egg yolks and lemon juice in food processor (or blender) and process for 20 seconds.  With machine running, slowly pour melted butter down through feeder tube.  Season with salt and pepper.  To keep warm, place in a thermos or use for up to 30 minutes.