1. Preheat oven to 425°F/220°C.
2. Cut the tops off the strawberries and cut into pieces. Set aside.
3. In a pot over low heat, combine egg yolks, heavy cream, sugar, and cornstarch. 4. Turn the heat up to medium-high, whisking constantly to prevent any lumps.
5. Once the mixture starts to thicken, add in the strawberries, stirring until smooth.
6. Transfer the cream mixture into a bowl, covering the top with plastic wrap and pressing the wrap down onto the surface of the cream to prevent a skin from forming. Chill.
7. In a pot, combine the water and butter, bringing it to a boil. Add the flour and stir until the dough comes together in a ball. Remove from heat.
8. Add in the vanilla and eggs one a time, stirring until the dough becomes a paste. Transfer the dough into a piping bag with a large round tip.
9. On a baking sheet lined with parchment paper, pipe 1-inch mounds.
10. Bake for 20 minutes until the pastry has risen considerably and the insides are dry.
11. Transfer the chilled pastry cream into a piping bag with a small tip. Poke a hole in the center of the bottom of each cream puff and fill each puff with the pastry cream.
12. Microwave the chocolate at 30-second intervals until smooth. Mix in coconut oil if using.
13. Dip the top of each filled cream puff into the chocolate, dripping off any excess.