Preheat oven to 350°F (180°C). Spray or brush an 8-in. (20-cm) round baking pan with vegetable oil.
In a large bowl, using an electric mixer, beat olive oil with eggs until light and pale, about 2 min. Beat in the yogourt, honey, rosemary, lemon zest and lemon juice. Set aside.
In a separate bowl, whisk together the all-purpose flour, semolina flour, baking powder and salt. Stir the flour mixture into the olive oil mixture just until combined. Do not overmix. Scrape the batter into prepared pan.
Bake in the centre of preheated oven until golden brown and a skewer inserted into centre of cake comes out clean, 30 to 35 min. Let cool in pan for 5 min. before inverting onto a rack to cool. Once cooled, sift icing sugar overtop to serve.