1. Preheat the oven to 425°F. Line a baking sheet with parchment paper.
2. In a small saucepan combine the water, milk, butter, and salt and bring to a boil, allowing the butter to melt. Remove from the heat and dump in the flour all at once, then stir vigorously to make a paste. Stir until the mixture forms a ball, pulling away from the sides of the pan, and is a bit glossy.
3. Transfer the batter to a mixing bowl and use an electric mixer to blend the dough as you add the eggs one at a time, blending until incorporated (you can also use a spoon for this, but be prepared to work!).
4. Transfer the mixture to a pastry bag with a large plain tip, or a large, sturdy freezer-proof zipper top plastic bag. If using a plastic bag, trim a very small triangle from one of the bottom corners of the bag. Pipe the mixture into 1-inch balls onto the prepared baking sheet, leaving at least 1-inch in between each ball. Dip a finger in water and press down the piped tip at the top of each puff so the top is smooth. Bake for 20 to 25 minutes, until light and somewhat hollow inside, when you tap them. Use a small sharp knife to cut a little slit in the side of each to let the steam escape. Cool on the baking sheet on a wire rack.
5. While the puffs are baking make the raspberry sauce. Combine the raspberries, sugar, cornstarch, and zest, if using, in a small saucepan. Heat, stirring frequently, over medium heat until the sauce comes to a simmer. Simmer for 1 to 2 minutes until thickened, and taste to see if you want to add more sugar. Strain through a fine-mesh strainer into a bowl, pressing against the strainer with the side of a spoon to get as much sauce through as possible, and scrape the strained sauce from the bottom of the mesh strainer into the bowl. Discard the seeds. Let cool slightly.
6. Just before serving, slice the puffs in half horizontally, and use a tablespoon to fill with the ice cream of your choice. Top the puffs with the slightly warm raspberry sauce and serve immediately.
- Mix and match ice cream flavors for a fun array of bite-sized desserts. Try fruit flavors, such as raspberry or strawberry, different versions of chocolate or vanilla or some of the fun combo flavors like Cookie Dough and Cherry Garcia.
- Try chocolate sauce instead of raspberry on some of the filled puffs.
- You can make the puffs ahead of time, and store them at room temperature in a tightly covered container. Fill and drizzle with the sauce just before serving.
- You can also fill them ahead of time and store in the freezer for up to one day. Let them sit at room temperature for 15 minutes before serving, and drizzle them with the sauce at the moment you serve them.