Step 1

Line or grease an 8 or 9-inch round springform round pan. Preheat the oven to 350F (180C).

Step 2

In a large bowl, add the sugar and the egg yolks (save the egg whites in a separate bowl). Beat with a hand mixer (or by hand) until light and foamy.

Step 3

Add the orange zest, orange juice, oil, and almond extract (or orange extract) if using. Beat for two more minutes.

Step 4

Add the almond flour and baking powder, and mix until combined and smooth.

Step 5

Beat the egg whites in a separate bowl until firm. Fold into the cake batter.

Step 6

Pour into the prepared pan, level, and sprinkle with almond slices. Bake for about 40 minutes or until golden and set. Test with a toothpick for readiness. Let cool, remove from the pan and serve with powdered sugar.