Divide the strawberry purée between 6 (3-ounce) popsicle molds (about 2 tablespoons each). Tap the molds on the counter to remove any air bubbles. If desired, use a small rubber spatula to clean up any drips on the interior of the molds for the cleanest layers. Freeze until completely solid, at least 1 hour. Meanwhile, make the white and blue layers.