Boozy popsicles. Enough said. We use these popsicle molds, but this recipe will work with whatever molds you have. Adjust the total volume of liquid in the recipe to match the total volume of your molds by adding a little more or less Prosecco.
Place the raspberries and sugar in a small pot and set over medium-high heat. Cook, stirring and mashing the raspberries with a spoon a bit from time to time, until sugar melts and most of the raspberries have broken down, 5 to 10 minutes. Pour raspberries into a fine-mesh strainer set over a 4-cup glass measuring cup. Stir and press the puree through the strainer, leaving seeds behind. (You'll inevitably lose some puree too. Don't worry about it.)
Let puree cool to room temperature. Then pour in Prosecco a little at a time, letting bubbles subside, until the total volume measures just shy of 30 ounces (or the total volume of your popsicle molds). Pour in lemon juice and stir well. Pour liquid into molds and freeze for an hour or two, then add popsicle sticks.
Freeze until solid, at least 8 hours, preferably overnight.