FOR THE CAKE – 1 stick of salted butter [113 grams, 4 ounces] at room temperature, plus extra to grease the pan – 1 cup of all-purpose flour [120 grams, 4.2 ounces]– ½ teaspoon of baking soda – ½ cup of sugar (white, granulated) (white, granulated) – 2 eggs (medium) – 2 tablespoon of mandarin juice – ¼ teaspoon of mandarin zest FOR THE SYRUP – Peel of a quarter of a mandarin orange – 1 cup of mandarin juice – ¼ cup of powdered sugar – Seeds of ½ vanilla pod