Use a food processor to pulse the butter, sugar, and salt. Then add the flour and pulse a few times. Add vanilla. Pulse again 3 times to incorporate .

Then put the dough onto a piece of parchment paper. Form a disc. Place another piece of parchment over it and roll it to 1/8 inch thickness. Then freeze for 45-60 minutes. Prepare choux, then cut into 2 inch diameter rounds and place over piped choux right before baking.

Preheat oven to 350 degrees F. Fit a piping bag with a large round piping tip. Line baking sheets with parchment. Set aside.

In a medium sized pot set over medium heat, combine the milk and water, butter, salt, and sugar. Stir to combine and stir as the butter melts.

As the mixture begins to boil remove from the heat and add the flour at once. Then mix it with a wooden spoon quickly to combine into a dough. It will be like a thick paste.

Return the pot to the heat. This is crucial to dry out the dough. Stir it constantly. It will turn into a ball and pull away from sides of pot. This takes about 90 seconds to 2 minutes.

Then remove from heat and put the dough into a stand mixer fitted with the paddle attachment. (You can also do this by hand, but put dough into a large mixing bowl and use the wooden spoon. )

Have mixer on low and stream in lightly beaten eggs (eyeball one at a time), allowing time after each addition to completely mix. Once it is fully smooth and mixed, pour batter into piping bag.

Pipe 2 inch mounds of choux. Flatten down with a wet fingertip, if needed.

Then remove craquelin from freezer. Cut out 2 inch rounds and place a round on each mound of dough.

Bake for 30-35 minutes, until golden and puffed. Do not open the oven during baking time!

They will be firm and hollow in the middle. Allow to cool on racks completely before filling.

In a saucepan set over medium low heat, combine 1.5 cups of milk, salt, and sugar. Stir to combine.

Then in a bowl, whisk the egg yolks with remaining milk and cornstarch.

Once the milk has heated to almost a simmer, temper it into eggs using a steady stream and whisking the eggs vigorously. Then pour back into saucepan. Whisk gently and frequently as it will thicken in 8-10 minutes. Once it thickens, remove from the heat and whisk in the praline paste, butter, and vanilla. Cool completely.

Then whip heavy whipping cream until stiff. Gently fold the cream into the pastry cream to lighten it. Fill the choux buns as desired.