Peel the lemon (see the video).
Add water to a pot and add 1/2 tsp.
lemon juice, 1 tsp.
sugar and 1/4 tsp.
Bring to a boil, then reduce heat and simmer for 30 minutes, or until the sugar dissolves.
Meanwhile, place the peeled lemon on a baking sheet, drizzle with the remaining lemon juice and sprinkle with the sea salt.
Bake at 350° for 45 minutes or until a skewer inserted in the center comes out clean.
Remove from oven and cool to room temperature.
Make lemon cake.
Watch the video to see how to make this classic lemon cake: