Step 1

For the lime layer: Heat 1 1/2 cups water in a small saucepan (or in a heatproof bowl in the microwave) until just simmering. Pour the lime gelatin powder into a medium bowl, then add the hot water. Stir until the powder has completely dissolved, about 2 minutes. Stir in the rum until combined. Transfer to a large liquid measuring cup. Divide evenly among 34 plastic shot glasses (1-ounce glasses). Refrigerate until the gelatin has set, about 45 minutes.

Step 2

For the strawberry layer: Heat 1 1/2 cups water in a small saucepan (or in a heatproof bowl in the microwave) until just simmering. Pour the strawberry gelatin powder into a medium bowl, then add the hot water. Stir until the powder has completely dissolved, about 2 minutes. Stir in the rum until combined. Transfer to a large liquid measuring cup. Carefully pour this mixture on top of the set lime layer in each shot glass, then return the glasses to the refrigerator to set completely, about 2 hours.

Step 3

For the topping: Meanwhile, with an electric mixer on medium speed, whisk the cream in a large bowl until it holds stiff peaks. Cover and refrigerate until ready to serve.

Step 4

Pipe or dollop the whipped cream on each shot, then decorate lightly with sprinkles. Serve chilled.