While eggs are cooking prepare your Hollandaise sauce. For the sauce: Place the 3 egg yolks, mustard, lemon juice in the blender and blend together. Melt butter in a microwave safe bowl for about 1 minute. Butter should be hot and bubbly. Next, stream melted butter into the mixture slowly while blending until mixture is a pale yellow and completely combined. You can add a dash of hot sauce here if you like a little spice in your sauce. Hollandaise sauce should be made and served right away so that it is warm.