Preheat your oven to 350°F (175°C). Lightly grease a 9-inch square baking pan and dust it with flour if desired. Preparing the pan ahead of time prevents sticking and makes removing slices much easier later.
In a medium bowl, whisk together the flour, baking powder, salt, cinnamon, and orange zest. Mixing these ingredients first ensures the baking powder and spices distribute evenly throughout the cake. This step helps create consistent texture and flavor.
In a large mixing bowl, beat the softened butter and sugar until the mixture becomes pale and fluffy. This process incorporates air into the batter and helps produce a lighter cake. Don't rush this step because it contributes significantly to the final texture.
Add the eggs one at a time, beating well after each addition. Pour in the milk and continue mixing until everything is smooth. The batter should look creamy and well blended without any visible streaks.
Gradually add the dry ingredient mixture to the wet ingredients. Stir gently until just combined to avoid overmixing. Overworking the batter can lead to a dense cake rather than a soft and tender crumb.
Add the chopped walnuts and fold them evenly into the batter using a spatula. The walnuts provide texture and a delicious nutty flavor. Make sure they are distributed throughout the mixture for balanced bites.
Pour the batter into the prepared baking pan and spread it evenly. Bake for approximately 40 minutes or until a toothpick inserted into the center comes out clean. The top should be lightly golden and slightly firm to the touch.
Allow the cake to cool in the pan for about 15 minutes. Once slightly cooled, cut it into squares or diamond-shaped pieces. Slicing before adding the syrup helps the sweet liquid penetrate every section more effectively.
Combine sugar, honey, and water in a saucepan over medium heat. Simmer gently for about 5 minutes, then stir in the lemon juice and cook for another couple of minutes. The syrup should be smooth, glossy, and slightly thickened.
Slowly pour the warm honey syrup over the sliced cake. Allow the cake to rest so it can absorb the syrup completely. As it sits, the flavors deepen and the texture becomes wonderfully moist and tender.