Pour ¾ cup of fresh apple cider into a shallow pan. Heat it over medium heat, allowing it to simmer gently for about 10-15 minutes until reduced by half. Stir in ½ cup of melted butter and let it cool slightly.

In a large mixing bowl, whisk together the cooled apple cider mixture with ⅓ cup of light olive oil and ½ cup of sour cream. Add 1 teaspoon of ground cinnamon and a pinch of salt. Mix until fully incorporated.

Gradually whisk the reduced cider mixture into the wet ingredients. In a separate bowl, sift together 2 cups of all-purpose flour, 2 teaspoons of baking powder, and ½ teaspoon of baking soda. Slowly fold the dry ingredients into the wet mixture.

Preheat your oven to 350°F (175°C). Line a square baking dish (8x8 inches) with parchment paper and grease it lightly. Pour the batter into the prepared dish.

Bake for about 22-25 minutes. Check for doneness by inserting a toothpick into the center; it should come out clean or with a few moist crumbs.

Remove the cake from the oven and let it cool in the dish for about 5 minutes. Brush the top with melted butter and sprinkle with cinnamon sugar.

Lift the cake out using the parchment paper, cut into squares and serve warm.