Place the popcorn in a large bowl, removing any unpopped kernels. Transfer to a warm oven.
In a saucepan, bring the water, sugar and corn syrup to a boil. Cook without stirring until the mixture turns golden. Remove from the heat. Add the butter and stir until it melts. Drizzle over the hot popcorn while tossing to coat well. Working quickly, use a spoon or measuring cup to remove about 250 ml (1 cup) of popcorn and gently press it into a 10-cm (4-inch) round cookie cutter. Repeat with the remaining popcorn. If the popcorn in the bowl becomes too cool, microwave it for a few seconds. Let the cakes cool for 30 minutes.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.