Preheat the oven to 180c. Grease a Bundt cake pan using cooking spray, and then dust with flour to coat it completely, tapping out any excess flour.
Sift the flour, baking powder, salt, baking soda, cinnamon, ginger and nutmeg into a medium bowl and set aside.
In an electric mixer fitted with a paddle attachment, beat the eggs, sugar and olive oil on medium speed until light and fluffy, 3 to 4 minutes. Then beat in the vanilla extract. Scrape down the sides of the bowl with a spatula, and then mix for 30 seconds. Turn the mixer to low and beat in the zucchini and walnuts until they are completely incorporated.
Pour the batter into the prepared pan, smoothing the top with a spatula. Bake the cake for 40 to 45 minutes. The cake is done when a tester inserted in the centre comes out clean and the cake has begun to pull away from the sides of the pan.
Serve with the Mandarin Orange Glaze and Walnut Olive Brittle.
Mandarin Orange Glaze:
In a small saucepan over medium-high heat, add the sugar and 4 tablespoons water. When the water has evaporated, the sugar will begin to caramelize. When it reaches a medium golden brown, add the mandarin orange juice. Next, whisk in the butter and heavy cream. To finish the sauce, add the mandarin orange segments.
Walnut Olive Brittle:
Line a baking sheet with a nonstick baking mat or with an oiled sheet of foil.
Heat the sugar and 1/4 cup water in a deep, heavy saucepan over low heat. Stir slowly with a fork until melted and pale golden in color. Gently swirl the pan and stir in the walnuts and black olives. Then immediately pour the caramel onto the prepared baking sheet, tilting the sheet to spread the caramel as thin as possible. Cool the brittle completely at room temperature. Break into small pieces with a spoon.