1. Heat oven to 350 degrees.

2. Coat the molds first with vegetable-oil spray, then lightly rub with room-temperature butter. Do not leave any lumps of butter in the indentations of the mold.

3. Set molds on a baking tray. To keep them level, prop them up with loosely crumpled aluminum foil.

4. Melt the butter and allow it to cool while proceeding with the recipe.

5. Using the whisk attachment on an electric mixer, beat together the eggs and sugar until tripled in bulk, 10 to 12 minutes.

6. Add the salt, vanilla, and lemon zest, mixing thoroughly. Add the flour in 3 batches, very quickly shifting speed from low to high after each addition. Add the melted butter in the same manner.

7. Using the whisk, scrape sides and bottom of the bowl, carefully blending batter so the butter doesn't settle to the bottom.

8. Fill the prepared molds three-quarters full. Bake until golden, about 10 minutes, depending on size of mold. Invert cakes onto wire racks as soon as they are removed from oven. When thoroughly cooled, glaze with Chocolate or White Chocolate Ganache.