Preheat oven (electric cooker: 225 °C/circulating air: 200 °C/gas: see manufacturer). Oil the pop-over tray, preheat in the oven.
Mix cinnamon and sugar for the filling. Wash, quarter and core the apple. Cut into small cubes. Mix with raisins and 2⁄3 cinnamon sugar.
For the dough melt butter, let it cool down a little. Mix eggs, milk and 1⁄2 TL salt with a whisk briefly. Stir in butter. Add flour at once and stir in quickly until the dough is just lump-free.
Then fill the dough into a container with a pouring spout (e.g. measuring cup). Remove hot sheet from the oven. Immediately fill each trough to 1⁄3 with dough. Spread the apple-raisin mixture over it. Pour the rest of the dough onto it.
Bake immediately in a hot oven for about 15 minutes. Then reduce the temperature (electric oven: 175 °C/circulating air: 150 °C/gas: see manufacturer). Continue baking for 10-12 minutes. Sprinkle pop-overs with remaining cinnamon sugar and serve warm.