10-20 minutes before starting the recipe, take out a sheet of puff pastry and let it partially thaw on the counter.
Yuzu Curd
Zest the lemon, then add the zest, yuzu juice, sugar, salt, egg and yuzu extract (if using) to a saucepan.
Set the saucepan over medium heat and constantly whisk until the mixture thickens and reaches at least 170°F / 76°C. (This took ~3 minutes for me)
Remove the curd from the heat and pass it through a fine mesh sieve to remove the zest and any unwanted egg bits.
Immediately add in the butter and whisk until the butter has melted and the mixture is smooth.
Place the curd in the freezer to set while assembling the danishes.
Cheesecake Filling
In a small mixing bowl, beat the cream cheese for ~1 minute to remove lumps.
In a small bowl, whisk the egg. Add 1 tbsp. of the whisked egg into the cream cheese, along with the vanilla and sugar.
Beat the mixture together until it is smooth, and save the whisked egg for the egg wash.
For the egg wash, whisk 1 tbsp. of milk into the whisked egg.
Yuzu Cheesecake Danish Assembly
Preheat the oven to 400°F / 205°C. Line a baking sheet with parchment paper.
Unfold the slightly thawed puff pastry and slightly roll it out so that it is at least 10" x 10".
Use a 3" biscuit cutter to cut out 9 danishes from the sheet. (Alternatively, you can cut the sheet into squares.)
Use a slightly smaller (about 2") biscuit cutter to slightly indent the center of each danish. Evenly spread about 2 tsp. of cheesecake filling in the center of each danish, then top with yuzu curd.
Brush the edges of each pastry with the egg wash, then bake for ~10-15 minutes or until the edges of the pastry are golden brown.
Garnish with powdered sugar & lemon or yuzu slices if desired. Serve and enjoy!