Preheat your oven to 350°F (175°C) and prepare an 8-inch springform pan by greasing it and lining it with parchment paper.

In a large mixing bowl, combine 3 eggs and 1 cup of sugar. Beat with an electric mixer on medium speed for 3-5 minutes until light and fluffy.

Sift together 1.5 cups of all-purpose flour and 2 teaspoons of baking powder in a separate bowl. Gradually add to the egg mixture while mixing on low speed along with 4 tablespoons of softened butter until smooth.

Gently fold in 1 cup of Greek yogurt until the batter is homogenous.

Chop the whole orange into pieces, blend in a food processor to make a purée, then add to the batter and mix gently until incorporated.

Pour the batter into the prepared pan and bake for 50–60 minutes, until a toothpick inserted comes out clean.

Cool in the pan for 15 minutes before transferring to a wire rack.

In a small saucepan, simmer 0.5 cup of orange juice and 0.25 cup of sugar until thickened, then brush over the warm cake.