Mix yogurt, sour cream, lime juice, lime zest, milk and sugar until smooth. Soak the gelatin in cold water and then while dripping wet, dissolve in a small saucepan over low heat and thoroughly mix with the lime mixture. Set for about 30 minutes in the refrigerator. Whip the cream. When the lime mixture thickens, stir in the whipped cream. Pour the yogurt mousse into dessert dishes and leave to set in the refrigerator.
Slice the baby pineapple into very thin slices. Place in a medium hot pan with butter and honey. Caramelize the pineapple slices until brown on both sides.
To serve, turn over the mousse ramekins, garnish with lime zest and pineapple slices while warm.