Place the whole oranges (peel and all!) into a saucepan and fill with water. Don’t worry if they float a bit—it’s totally fine. Bring the water to a boil, then cover with a lid and let the oranges simmer for 30 minutes.
Once done, drain the water and let the oranges cool down.
Preheat your oven to 160°C fan, 180°C (350°F), or gas mark 4.
Slice each orange in half and remove any visible pips. Pop the orange halves into a blender or food processor and blitz until completely smooth.
In a mixing bowl, whisk together the eggs, sugar, and granulated sweetener. Stir in the oil and your blended orange purée, mixing until everything is nicely combined.
Gently fold in the almond flour and baking powder until fully incorporated.
Line the base of an 8-inch springform pan with parchment paper, and lightly grease the sides with low-calorie spray.
Pour the cake batter into the pan, then give the tin a little tap on the counter to help spread it out evenly. Sprinkle the top with sliced almonds.
Bake for about 50 minutes, or until a skewer inserted in the center comes out clean. (Tip: After around 40 minutes, you may want to loosely cover the top with foil to stop it from browning too much.)
Let the cake cool, then carefully remove it from the pan. Slice into 8 pieces and give it a light dusting of icing sugar.
Enjoy every citrusy bite! 🍊🍰