For the coffee cream,

In a bowl with a whisk, mix the yolks and the egg until they are foamy. Add the sugar (70 grams) and cornstarch, and mix until they are all incorporated.
In a medium saucepan, heat the milk with the butter, remaining sugar (70 grams), and salt, stirring to dissolve the sugar. As it begins to boil, remove from the heat and slowly add to the yolk mixture, whisking all the time.
Return the mixture to the saucepan and cook over medium heat until it thickens, stirring constantly. Remove from heat, add the coffee extract, and pass through a sieve if you see lumps. Cool the custard in a bowl with water and ice. Cover with plastic wrap pressed directly into the custard. Refrigerate until ready to use. You may make it 2-3 days before use.

For the cake,

Place the milk, eggs, flour, sugar, salt, and bourbon in the blender and process for 15 seconds. With a spatula, clean the sides of the jar to ensure that all the flour mixes. With the blender on low speed, add the butter and blend for 10 seconds. Refrigerate overnight.

Let the batter return to room temperature. Heat over medium heat in an oiled 8″ non-stick pan. Once hot, add 1/4 cup batter, moving to cover the entire bottom of the pan. Cook for 30 seconds to 1 minute until the crepe is golden brown, lift the edges with a knife or spatula, and use your fingers to turn the crepe. Cook for 30 seconds to 1 minute on the other side.

Stack on a plate and let cool completely before using it.

To assemble the cake,

Whip the cream in a cold bowl until stiff peaks form. Gently mix with the coffee custard.

Fill the cake, alternating pancakes and coffee cream, place a thin layer of cream over the middle and thicker at the edges.

Decorate. Keep in the refrigerator.