Preheat your oven to 425˚F. Line a rimmed baking sheet with either a Silpat mat or parchment paper to prevent sticking.
In a medium saucepan, combine 1/2 cup water, 1/2 cup milk, 8 Tbsp unsalted butter, 1 tsp granulated sugar, and 1/4 tsp salt. Bring this mixture to a gentle boil over medium heat.
Once boiling, remove the saucepan from heat and stir in 1 cup all-purpose flour all at once using a wooden spoon. Mix until the dough starts to come together and forms a ball.
Return the saucepan to medium heat, stirring constantly for about 1 and a half to 2 minutes. This helps to cook the flour slightly and release excess moisture. You’ll know it’s ready when a thin film forms on the bottom of the pan.
Transfer the dough to a large mixing bowl. Using an electric mixer on medium speed, beat the dough for about 1 minute to cool it slightly.
Add 4 large eggs one at a time, making sure each egg is fully incorporated before adding the next. Beat for another minute until the mixture is smooth and forms a thick ribbon when lifted with a spoon.
Transfer the dough into a piping bag fitted with a 1/2 inch round tip. Pipe out 28 puffs, each around 1 and 1/2 inches in diameter and 1/2 inch tall. Space them at least 1 inch apart on the baking sheet.
If the puffs have peaks, lightly wet your fingertips and smooth them down before baking to ensure they rise evenly.
Bake in the preheated oven for 10 minutes. Without opening the oven door, reduce the temperature to 325˚F and bake for an additional 20 to 22 minutes or until they’re golden brown on top.
Once baked, transfer the puffs to a wire rack to cool completely.
In a large mixing bowl, combine 2 cups heavy whipping cream, 4 Tbsp granulated sugar, and 1 tsp vanilla extract. Beat on medium-high speed until fluffy with stiff peaks, which should take about 2 minutes.
Fill a piping bag fitted with a large open star tip and fill the cooled puffs with the whipped cream. There are two methods: either pipe the cream into the sides of each puff or cut the tops off and fill them, adding a raspberry if desired before replacing the tops.
Dust the filled Cream Puffs with a sprinkle of powdered sugar before serving.