Pour boiling water over gelatin in a heatproof bowl.

Stir until the gelatin is completely dissolved.

Combine instant coffee and cocoa powder in a saucepan.

Add sugar and evaporated milk to the saucepan.

Stir the mixture over low heat until the coffee is dissolved and the mixture is hot, but not boiling.

Remove the saucepan from the heat and allow the mixture to cool until it is lukewarm.

Stir in the dissolved gelatin mixture and vanilla extract.

Pour the mixture into a 4-cup oiled mold.

Refrigerate for at least 4 hours, or until the jelly is firm.

To serve, dip the base of the mold briefly into hot water, then invert the jelly onto a serving plate.