For the salty caramel sauce: Distribute the sugar evenly in a small saucepan. Heat over very low heat, stirring regularly to mix the sugar. As soon as the caramel is amber, pour hot cream drop by drop, stirring constantly with a whisk (mind the squirt). When the bubbles have disappeared, leave the sauce on the cooker to allow it to slightly thicken. Stir constantly. Turn off and add butter mixed with salt at room temperature. Then fill in a jar and put in the fridge.

For the crumble: Mix melted butter, flour, sugar and cinnamon with your fingertips in a bowl. Let the crumbly mixture rest in the fridge until completing the muffins.

For the muffins: Beat egg with yolk and sugar in a bowl until creamy with an electric whisk. Add lemon zest and sieved flour with baking powder. Mix with a spoon, add milk and melted butter at room temperature and mix in.

Distribute the dough in 6 buttered and floured muffin molds filling them until 3/4 full. Thinly slice the Pinova apple with the peel with the help of a knife or mandolin. Put 3 slices on each muffin and sprinkle with the previously prepared short pastry crumble. Bake in the preheated oven at 180° for 25 minutes (make the toothpick test). Remove from the oven and allow to cool completely before serving with the caramel sauce.