Mix the lemon Jell-o with the boiling water. Let cool to room temperature.
Combine the caek mix, oil, eggs and cooled Jell-o. Bake in a 9-13 pan for 40 to 45 minutes at 350 degrees.
When the cake is done, poke holes all over the top with a toothpick. Mix powdered sugar with lemon juice to make a thin icing, then spoon this over the cake while still warm.