Preheat the oven to 350ºF (180ºC). Line the bottom of an 8-inch square baking pan with parchment paper. Grease and flour the insides.
In a medium-sized bowl, whisk together the flour, baking powder, baking soda, and salt until well blended.
In a large bowl, beat the sugar, orange zest, oil and eggs with an electric mixer at medium speed, until smooth and creamy. Add the orange juice and the extracts and beat until blended. With the mixer on low speed or by hand, beat in the flour mixture in two additions followed by half of the sour cream after each addition. Mix just until smooth and combined.
Transfer the batter to the baking pan. Bake until the top looks golden and a toothpick inserted into the center of the cake comes out clean, about 20-25 minutes. Do not over bake. Let the cake cool in the pan for 10 minutes, then remove it from the pan and transfer it to a cooling rack. Alternately, if you want to transport the cake in the pan, you can let it cool in the pan.