Grease 13x9 pan.
Combine all ingredients in a pan. Bring to a boil over medium heat, stirring constantly. Boil for a minute.
Pour into a prepared pan and refrigerate until set.
Dust cutting board with sugar. Use a spatula to loosen sides and turn out onto the cutting board.
Dust top of Jello with sugar.
Use a shamrock-shaped cookie cutter to cut out gumdrops.
Roll edges in extra sugar and set onto wax paper for 1 hour to dry out slightly.
Store in an airtight container.