Zest the lemon (yellow part only), then cut it and squeeze the juice
Whisk 1 egg, sugar, salt, and cornstarch until smooth
Add about 3 tbsp lemon juice to the egg mixture
Heat the milk with a little sugar until hot (small bubbles around the edges)
Slowly whisk the hot milk into the egg mixture
Return the mixture to the saucepan
Cook over medium heat, stirring constantly, until thick
Strain the cream and mix in all the lemon zest, then set aside to cool slightly
Mix eggs, sugar, and salt in a separate bowl
Add yogurt, remaining lemon juice, and melted butter, then mix well
Sift in flour and baking powder, then mix until smooth
Grease and line the pan with parchment paper
Pour in the batter and level it
Pipe the lemon cream on top in a spiral or pattern
Bake at 350°F (175°C) for 40–45 minutes without convection
Turn off the oven and leave the cake inside with the door slightly open for a few minutes
Remove and cool completely before taking out of the pan
