Preheat your oven to 180C (350F). Line a 2LB loaf tin with baking paper, letting the edges hang over the sides of the tin. Pulse the pecans in a food processor until finely ground.
Put the orange zest, olive oil, sugar, eggs, orange juice and yogurt in a mixing bowl and either beat together to combine or vigorously mix together with a wooden spoon.
Stir in the ground pecans and sift in the flour, spices, salt and raising gents.
Mix well until you have a smooth batter.
Transfer the batter into the tin and level. Bake for 50-55 minutes – testing with a skewer to see whether the cake is ready. The skewer should come out clean and the cake should feel firm on top.
Cool in the tin for 10 minutes and then lift out using the paper. Let the cake cool completely before slicing in half, if you wish to fill it.
Orange Syrup (optional)
Put the orange juice and sugar in a saucepan and stir over low heat until the sugar has dissolved. Brush this over the inside of the cake. Any leftover syrup can be used in drinks.
Make the filling
Whisk cold double cream and icing sugar together until you have firm peaks. Transfer to a piping bag fitted with a large star tip
Pipe a generous amount of filling over the bottom layer and top with the second.
Glaze and decorate
Put all the glaze ingredients in a bowl and mix together with a spoon, adding a bit more orange juice if needed until you have a thick glaze.
Drizzle the cake with the glaze, letting it drip down the sides. Add orange slices (or candied orange slices) and dust with icing sugar.