Whisk (with a hand whisk) together the eggs, sugar, and vanilla extract. Mix vigorously until the mixture becomes light, pale, and foamy.
Gradually add the oil and orange juice while whisking.
Add the sifted flour and baking powder to the wet ingredients.
Add the tahini and chocolate chip and mix just until everything is combined.
Pour the batter into the prepared cake pan and smooth the top with a spatula. Tap the pan gently on the counter to release any air bubbles.
Place the cake pan in the preheated oven and bake for approximately 45-50 minutes or until a toothpick inserted into the center comes out clean.
Once baked, remove the cake from the oven and allow it to cool in the pan for about 10-15 minutes. Then, transfer it to a wire rack to cool completely.