Add ½ cup (100 grams) granulated sugar into a small fry pan, along with 2 tbsp water and heat with a medium heat, shake the pan so everything is well mixed

Meanwhile, peel 2 oranges and then cut into ¼ inch (.635 cm) thick rounds

Line an 8-inch (20 cm) round baking pan with parchment paper and grease the sides with nonstick cooking spray

After about 8 minutes and all the sugar has dissolved and you´ve ended up with a dark amber caramel sauce, remove from the heat and add into the baking pan, add the slices of orange over the caramel, all in a single layer

Crack 3 eggs into a large bowl, whisk together, then slowly add in 1 cup (200 grams) granulated sugar while you continue to whisk, once all the sugar has been added, add in the greek yogurt, the sunflower oil and the juice of 1 orange (about 2 tbsp / 30 ml), whisk together until well mixed, then add in the flour, baking powder and salt, mix together until you end up with a thick batter with no lumps

Pour the cake batter into the baking pan, making sure it´s all in a flat layer once poured

Add into a preheated oven, bake only (bottom heat), 180 C - 350 F

After 40 minutes remove from the oven, pierce with a toothpick, if it comes out cleanly the cake is fully cooked through, let it rest for 15 minutes, then place a plate over the pan and flip, remove the baking pan and parchment paper, enjoy!