In a tall narrow container (glass jar or stemless wine glass) that an immersion blender will fit into. This is how I find I make aioli that comes out great every time, I have used drink makers, blenders, but they never seem as good as the whipping action of an immersion blender.
Add egg yolk, vinegar, mustard, olive oil, and salt to the glass jar
Place the immersion blender into the jar and begin blending, moving the blender up and down to emulsify
Once it's blended, add in the cranberry sauce and blend until smooth
add additional salt if desired