Whisk the egg yolks and milk together in a medium saucepan.

Whisk the cornstarch, sugar, and salt into the saucepan.

Bring mixture to a boil over medium heat. Reduce heat to medium-low and let cook, whisking constantly, 2-3 minutes.

Whisk in the butter and vanilla extract and let boil for 1 minute, whisking constantly.

Strain the hot mixture into the bowl to remove any lumps.

Cover bowl with plastic wrap, pressing the wrap directly onto the hot surface of the pastry cream to make sure a skin doesn’t form.

Refrigerate pastry cream for 2-3 hours (best if overnight) before using.

Preheat oven to 400F.

Line two baking sheets with parchment paper and set aside.

Bring your eggs up to room temperature. If cold, place them in a bowl filled with warm water for 5-10 minutes.

Cut the butter into cubes and set aside.

Measure out your flour and set aside.

Crack the room-temperature eggs into a small pitcher/small bowl and set aside.

Set up your stand mixer with a mixing bowl and paddle attachment. If you’re using a hand-mixer, attach your beaters and have a large mixing bowl ready.

Have a clean pastry bag and large piping tip (or scissors) at the ready.

Bring the water and the cubed butter to a rolling boil in a large saucepan over medium heat, about 5 minutes. Stir occasionally to make sure the butter melts before the mixture begins to boil.

Add the flour into the saucepan and stir vigorously with a wooden spoon until clumps of flour have disappeared and a small ball of dough has formed. Turn off stove and remove saucepan from heat.

Immediately turn out the hot dough into the mixing bowl of the stand mixer. Beat the paddle through the dough for 30-30 seconds to release steam.

Beat in the eggs on low, one at a time, until the dough is shiny and smooth. You might not need all the eggs.

Bake eclairs for about 40 minutes, until they’re deep golden brown and make a hollow sound when you tap them. (Careful! Hot!)

Remove eclairs and immediately poke a slit on the bottom of each with a sharp knife to release steam. Transfer eclairs to a wire rack to cool completely.

Pour chocolate chips into a small bowl.

Heat the cream and salt in a small saucepan over medium heat until boiling.

Pour the boiling cream over the chocolate chips. Use a spoon or spatula to ensure all chips are completely covered by the cream, then let mixture sit undisturbed for one minute.

Use a rubber spatula to slowly stir the cream and chocolate chips together into a smooth, shiny ganache. This will take a few minutes.

Once smooth, stir in the vanilla extract.

Cover ganache with plastic wrap and let cool for about an hour. Ganache should be thick, shiny, and pourable.

Dip tops of cooled, filled eclairs into cooled chocolate ganache, then let sit to harden on a cooling rack.