Melt and cool butter to room temperature first.

Separate egg yolks, then place in a blender.

Add dijon mustard, lemon juice and salt.

Blend on high for about 15 seconds.

Turn the blender on low. While it's running, add the butter in a slow, steady stream.

Keep blending until a thick sauce forms.

Serve over eggs, vegetables, or really anything else. Hollandaise will keep in the fridge for about 5 days.