Soak oranges in schnapps for at least 1 hour – drain just before use.
Butter an 8x8x2 pan. Then line with wax paper or plastic wrap. (I prefer wax paper)
In a double boiler* - melt chocolate, sweetened condensed milk and butter until smooth and thick.
Remove from heat. Add vanilla and stir until combined. Add drained oranges. Pour into pan. Cool. Tip: let cool outside of the refrigerator for 30 minutes so that no condensation mars the top. Refrigerate overnight. Remove from pan. Cut into pieces. Store in a covered container.