Step 1: Make the Choux Pastry

1. Preheat the Oven: Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper or a silicone baking mat.
2. Combine the Wet Ingredients: In a medium saucepan, combine the water, milk, butter, and salt. Place over medium heat, stirring occasionally until the butter melts and the mixture comes to a simmer.
3. Add the Flour: Once the mixture is simmering, add the flour all at once, stirring quickly with a wooden spoon until the dough comes together and forms a ball. Continue to cook and stir for 1-2 minutes to dry out the dough slightly.
4. Incorporate the Eggs: Remove the saucepan from the heat and allow the dough to cool slightly for 5 minutes. Then, one at a time, add the eggs, beating well after each addition until the dough is smooth and glossy.
5. Pipe the Pastry: Transfer the dough into a piping bag fitted with a large round tip. Pipe small mounds of dough (about 1 1/2 inches in diameter) onto the prepared baking sheet, spacing them about 2 inches apart.
6. Bake the Pastry: Bake in the preheated oven for 25-30 minutes, or until the puffs are golden brown and crisp. Do not open the oven during the first 20 minutes to ensure they puff up properly.
7. Cool: Allow the puffs to cool completely on a wire rack.

Step 2: Prepare the Strawberry Cream Filling

1. Whip the Cream: In a chilled mixing bowl, beat the heavy whipping cream with powdered sugar and vanilla extract until soft peaks form.
2. Add the Strawberries: Gently fold in the diced fresh strawberries into the whipped cream until evenly incorporated.
3. Chill: Keep the strawberry cream filling in the fridge while you prepare the puffs.

Step 3: Assemble the Cream Puffs

1. Cut the Puffs: Once the puffs have cooled completely, slice each puff in half horizontally, creating a top and bottom.
2. Fill with Cream: Spoon or pipe the strawberry cream filling onto the bottom half of each puff.
3. Top with the Lid: Place the top half of the puff over the filling to close the cream puff.

Step 4: Add Optional Toppings

1. Dust with Powdered Sugar: Lightly dust the top of each cream puff with powdered sugar for a sweet finish.
2. Drizzle with Chocolate: If desired, drizzle melted chocolate over the cream puffs for an extra touch of decadence.