Cake green??? Help?

My mother gave me a very traditional simple bundt cake recipe: - 7 eggs (fresh) - 200g of sugar - 200g of flour

She instructed me to beat the eggs with sugar with a hand mixer at medium speed for exactly 10 minutes. I then rigorously mixed the flour into the mixture with a spoon. I also decided to add a 1/2 teaspoon of baking powder. Then, I baked at 350°F for 40 mins.

The first time I made this cake it turned out perfectly fine, except it didn't rise as much as I thought it would. The second, third and tragically fourth time the cakes all came out looking like they do in the pictures.

I baked them all the same temperature for the same time (+-10 mins). I got a brand new pack of sugar, tried to get fresher eggs, brand new flour, I folded in the flour a lot more gently... None of these things made a difference.

Please help me figure out why God hates me. I just want simple, delicious fluffy cake