Preheat oven to 350°F (177°C). Grease 6-7 six-ounce ramekins with butter or nonstick spray. Place into a large baking pan or casserole dish. The cakes will bake in a water bath inside the casserole dish.

Whisk egg yolks, milk, melted butter, lemon zest, lemon juice, and vanilla extract together in a large bowl. Whisk in the flour, salt, and 3/4 cup (150g) of sugar until combined. Set aside.

In a medium bowl using a handheld or stand mixer fitted with a whisk attachment, beat the egg whites on medium-high high speed into soft foamy peaks, about 1-2 minutes. Sprinkle the remaining 1/4 cup (50g) of sugar on top, then beat into stiff glossy peaks, about 1-2 minutes. (Stiff peaks hold their shape when you lift the beaters/whisk.)

Spoon about 1/3 of the egg whites into the lemon batter. Working slowly and carefully so as not to deflate the egg whites, gently fold together until combined. Gently fold in another 1/3 of the egg whites until combined, then fold in the remaining egg whites. Batter will be thick and airy.

Divide between greased ramekins, filling nearly to the top. In all my recipe testing, I got either 6 or 7 cakes from this amount of batter. (Depended on how much the egg whites deflated.)

Without splashing into the ramekins, slowly pour hot water into the casserole dish around the ramekins, about halfway up the sides of the ramekins. If it’s easier, you can transfer the casserole dish to the oven first, then carefully pour in the hot water.

Carefully place the casserole dish/baking pan in the oven. Bake until the lemon cakes are puffy and lightly browned on top, about 35-40 minutes. Overbaking will cook the pudding on the bottom of the cakes, so I usually remove them at 35 minutes.

Using tongs or an oven mitt, remove the cakes from the casserole dish and place on a wire rack set over a baking sheet or kitchen towel to catch any dripping water. Cool cakes for 15-20 minutes before serving. You can serve warm or wait until they cool to room temperature.

Garnish with confectioners’ sugar and/or fresh berries or lemon slices, if desired.

Cover leftover cakes tightly and refrigerate for up to 3 days. Warm in the microwave, if desired, before enjoying.