Preheat the oven to 325ºF. Grease & flour the sides of an 9-inch springform pan or round cake tin; line the bottom with parchment.
Add the oil, sugar, eggs, and honey to a deep bowl. Whisk until well blended.
Add the apples, flour, baking powder, baking soda, salt, orange & lemon zest, and walnuts. Stir to mix; the batter will be a bit thick.
Spoon into the prepared cake tin. Bake until golden, edges pull slightly away from the side, and a skewer inserted in the center comes out clean, 55 to 60 minutes.