Preheat oven to 350°F. Lightly coat 9-inch springform pan with olive oil. Set aside.
In a medium bowl, whisk together AP flour, semolina flour, baking powder, baking soda, salt and ground cinnamon. In large bowl, whisk together ¼ cup sugar and olive oil. Add in egg yolks and whisk until combined. Using a spatula, fold in dry flour mixture in two additions. Fold in milk and orange zest.
Using an electric mixer, beat egg whites using a whisk attachment until foamy. Slowing add in remaining ¼ cup sugar and beat until firm peaks. Fold egg whites into cake batter in two additions. Transfer to prepared pan. Smooth top using a mini offset spatula to level batter.
Bake for 20-25 minutes until cake is set and a toothpick inserted into center comes out clean. Using a toothpick or the tines of a fork, pierce the cake all over. Slowly drizzle ½ cup of orange syrup over the cake. When the syrup is absorbed, about 5-10 minutes later, pour another ½ cup of orange syrup over the warm cake. Leave cake to cool in pan. Once cake is at room temperature, release cake from cake.
Place candied orange slices over the cake. Sprinkle pistachios. Cut into servings and serve with additional orange syrup.