Preheat the oven to 340°F (170°C).
Grease the baking pans with cooking spray (2 Long loaf pans or 9-Inch fluted tube pan) In a large bowl, whisk the eggs, heavy cream, sugar, salt, and vanilla extract for about 2 minutes until slightly thickened.
Add the flour and baking powder, and mix just until a smooth batter forms without lumps.
Spread the batter in the baking pans.
Drizzle tahini and honey on top, then gently mix them into the batter with a spoon or a skewer.
Bake for about 40-50 minutes, until the cakes have risen, are springy to the touch, and a toothpick inserted into the center comes out almost dry.
Let cool, then crumble halvah on top or dust with powdered sugar before serving.