Preheat the oven to 160°C fan. Grease and line an 8inch round cake tin with baking parchment.
Place the saffron in a pestle and mortar with the sugar and grind to a powder, then transfer to a bowl. Warm the milk, add the saffron mixture, then set aside to infuse.
In a medium bowl, whisk together the flour, baking powder, bicarbonate of soda, salt, and ground cardamom.
In a large bowl, whisk together the olive oil, sugar, eggs, vanilla extract, orange juice, and orange zest. Stir in the saffron-infused milk and yoghurt, mixing until smooth.
Gradually add the dry ingredients to the wet ingredients, whisking until just combined.
Pour the batter into the prepared tin.
Bake for 30–35 minutes, or until a cocktail stick inserted into the centre comes out clean.
Allow the cake to cool in the tin for 10 minutes, then transfer to a wire rack to cool completely.
Gently heat the marmalade in a small saucepan until melted. Brush the surface of the cake with the warm marmalade, then sprinkle with granulated sugar. Decorate with edible flowers—I used dandelions, daisies, and pansy petals. Serve with Greek yogurt or crème fraîche.