Grandma Mary's Cream Puffs

Preheat oven to 400°F (200°C). Line two baking sheets with parchment paper. (5 minutes)

In a saucepan, combine water, butter, and salt for the pastry. Bring to a rapid boil over medium-high heat. (5 minutes)

Remove from heat and add the flour all at once. Stir vigorously with a wooden spoon until the mixture forms a smooth ball and pulls away from the sides of the pan. (3 minutes)

Transfer the mixture to a large mixing bowl. Let cool slightly for about 5 minutes. This prevents the eggs from cooking when added.

Beat in the eggs one at a time, ensuring each egg is fully incorporated before adding the next. The dough should be thick and shiny. (8 minutes)

Spoon or pipe the dough onto the prepared baking sheets in 12 equal dollops, leaving about 2 inches between each. (7 minutes)

Bake in the preheated oven for 30 minutes, swapping the baking sheets halfway through to ensure even baking. The puffs should be light golden brown and well-risen. (30 minutes)

Remove from the oven and transfer to wire racks to cool completely. (30 minutes)

While the puffs are cooling, prepare the custard filling. In a medium saucepan, whisk together milk, condensed milk, sugar, eggs, and salt. (5 minutes)

Heat over medium heat, stirring constantly, until the mixture begins to steam. (7 minutes)

In a small bowl, whisk the cornstarch with 2 tablespoons of the hot milk mixture to create a slurry. This prevents lumps from forming in the custard.

Pour the cornstarch slurry into the saucepan with the remaining milk mixture. Cook, stirring constantly, until the custard thickens to your desired consistency. (5 minutes)

Remove from heat and stir in the vanilla extract. Continue stirring for another minute to cool slightly. (2 minutes)

Transfer the custard to a bowl, cover with plastic wrap (pressing the wrap directly onto the surface to prevent a skin from forming), and let cool for about 10 minutes. The custard will thicken further as it cools. (10 minutes)

Once the cream puffs and custard are cool, cut the tops off the puffs with a serrated knife. Fill each puff generously with the cooled custard. Replace the tops. (10 minutes)

Refrigerate the filled cream puffs for at least 1 hour before serving to allow the custard to set and the puffs to soften slightly. (60 minutes)