Preheat oven to 180°C (thermostat 6). Generously butter a tart or gratin dish. I personally use a 24cm diameter springform pan.

Peel, core, and thinly slice the apples. Evenly distribute the apple slices on the bottom of the buttered mold.

In a bowl, beat the eggs and sugar until light and fluffy. An electric whisk is ideal, but you can do it by hand; it just takes a little longer.

Add the plain yogurts, milk, and vanilla extract to the egg-sugar mixture. Mix gently but thoroughly.

In a separate container, sift together the flour and baking powder. Add this mixture to the previous mixture, gradually incorporating and mixing gently until a smooth batter is obtained without lumps. Add a pinch of salt.

Gently pour the batter over the apples in the mold, spreading evenly.

Bake for 35 to 40 minutes, or until the flan is golden brown and firm to the touch. Check the doneness with the tip of a knife: it should come out clean.

Let the flan cool completely in the mold before carefully unmolding it. Patience is the mother of all good things, let it cool properly.

Serve the flan warm or cold, as preferred. I personally love warm flan with a scoop of vanilla ice cream!