Cut baked potatoes in half lengthwise. 

Scoop potatoes from shells, leaving shells intact. 

Mash the scooped-out potato flesh while hot. Set aside.

Sautè onion in margarine until lightly golden. 

Combine potatoes, onion, spices and egg yolk. 

Place mashed potatoes into piiping bag and pipe into shells. 

Garnish with chopped parsley and red paprika.