When it boils, immediately take the pan off the heat. Stirring with a wooden spoon, add all the flour at once
and stir hard until all the flour is incorporated, 30 to 60 seconds. Return to the heat and cook, stirring, 30 seconds.
Scrape the mixture into a mixer fitted with a paddle attachment (or use a hand mixer). Mix at medium speed. With the mixer running, add 3 eggs, 1 egg at a time.
Stop mixing after each addition to scrape down the sides of the bowl. Mix until the dough is smooth and glossy and the eggs are completely incorporated.
The dough should be thick, but should fall slowly and steadily from the beaters when you lift them out of the bowl. If the dough is still clinging to the beaters, add the remaining 1 egg and mix until incorporated.
Transfer the dough to a pastry tube with a large round fitting.
Pipe dollops ont a baking sheet lined with parchment paper.
Wet your finger and press down any tips.
In a bowl combine the yolks and sugar.
Brush lightly with an egg wash.
Bake at 425F for 15 minutes then lower temp to 375 and bake an additional 10 minutes.
For the Custard:
In a medium saucepan, heat the milk and vanilla bean to a boil over medium heat. Immediately turn off the heat and set aside to infuse for 15 minutes.
Whisk the egg yolks and sugar until light and fluffy. Add the cornstarch and whisk vigorously until no lumps remain.
Whisk in 1/4 cup of the hot milk mixture until incorporated.
Whisk in the remaining hot milk mixture, reserving the saucepan. Pour the mixture through a strainer back into the saucepan.
Cook over medium-high heat, whisking constantly, until thickened and slowly boiling. Remove from the heat and stir in the butter. Let cool slightly. Cover with plastic wrap, lightly pressing the plastic against the surface to prevent a skin from forming. Chill at least 2 hours or until ready to serve. The custard can be made up to 24 hours in advance.
For the Strawberry Sauce:
In a saucepan combine the sliced strawberries, lemon, water and sugar and bring to a boil over medium heat.
Macerate the strawberries in the pan and allow to simmer for 10 minutes.
Strain the juice into a bowl, then transfer back to the pan and simmer for an additional 12-15 minutes.
Chill for at least one hour.
Time to combine everything!
This is optional but I folded some whipped cream into the custard to lighten the filling up.
Mix in the strawberry sauce.
Pipe the filling into the puffs.
Bring 1/2 cup cream to a boil and immediately pour over the white chocolate, whisking until smooth. Add in the red food dye if desired. You could also just use semisweet chocolate for a darker finish.