Preheat oven to 325°F. Place the butter and sugar in a food processor and process until well combined. Add the orange rinds, almonds, eggs, and flour and process until combined. Pour the mixture into a lightly greased 9” round springform cake tin lined with non-stick baking paper. Bake for 1 hour or until cooked when tested with a skewer. While the cake is baking, make the orange syrup. Place the orange juice, sugar, vanilla bean, and seeds in a small saucepan over low heat and stir to dissolve the sugar. Bring to a simmer and cook for 10 minutes or until the mixture has thickened and is syrupy. Discard the vanilla bean and pour half the hot syrup over the hot cake. Stand in the tin for 10 minutes. Remove the cake from the tin and serve with the yogurt and remaining syrup.