For hollandaise sauce, add lemon juice and yolk to metal bowl and beat until doubles in size. Place bowl over double boiler or over a pot with boiling water. Ensure water does not touch bottom of bowl. Pour in melted butter and whisk until incorporated. Careful not to allow egg to cook. Remove from heat, add chili powder and smoked paprika and cover, mix and set aside.
Add about 4 inches water to a high rimmed skillet or small pot. Place French Baguette into oven on middle rack and let heat for about 10 minutes. Watch to prevent burning.
In medium pan, add onion and cook for about 7 minutes, remove from pan. Add remaining 1 tablespoon butter to pan and add asparagus, season with salt, pepper. Add 1 tablespoon water and cover and cook about 5-7 minutes.
While asparagus is cooking, add vinegar to boiling water and then carefully add eggs. I used silicone eggs cups to make it a bit easier. Cover and cook for 3 minutes.
Top bread with eggs, onions and asparagus. Spread onions around and top with sauce. If sauce it thick, add 1 teaspoon water.