Prepare a 27 cm / 11 inch round springform cake pan, grease it lightly butter and line with parchment paper.
Preheat the oven to 160°C / 325°F / Gas Mark 3, no fan (if you have convection oven, reduce the temperature by about 20 degrees).
Using a mixer, whisk the eggs with sugar until light and fluffy, it will take about 4-5 minutes.
Slowly pour in the oil in a thin stream, mixing at the lowest speed.
Mix the honey with vanilla extract together, slowly pour in a thin stream, mixing at the lowest speed.
In a separate bowl, add the flour, baking powder, baking soda, salt and cinnamon, whisk to combine.
Add the flour mixture to the mixing bowl, fold in with a silicone spatula until just combined, not longer.
Peel and core the apples, cut into 1.5-2 cm / ¾ – 1 inch cubes. Roughly chop the walnuts.
Add the apples and nuts to the batter, fold in gently with a spatula.
Pour the batter into the prepared cake pan.
Bake for about 1 hour and 10 minutes. The baking time may slightly vary, depending on the oven. A cake tester or a wooden skewer, stuck in the center of the cake, should come out clean.
Wait until partially cooled, then cut into servings. Sprinkle with powdered sugar and enjoy!