Preheat oven to 325F (170C). Grease and flour a deep* 8" round cake pan, line with parchment.
In a medium bowl, whisk flour and baking powder. Set aside.
Beat butter, sugar, and lemon zest on med-high until pale and fluffy (2-3mins). Add eggs one at a time along with one tablespoon of flour mixture for each egg. Fully incorporate after each addition.
Gently fold in flour mixture, then lemon juice.
Bake for approximately 1 hour or until a cake tester comes out clean. Cool in pan for 10mins then turn out onto wire rack to cool completely.
Candied Lemon Slices:
Place sugar and water in a large, shallow, saucepan. Bring to a simmer and stir until dissolved. Gently lay the lemon slices in a single layer in the saucepan. Simmer for 15mins, turning over half way through.
Carefully remove slices from pan, dripping off excess syrup, and place on a parchment lined baking sheet. Allow to dry at room temperature. Dip in granulated sugar if desired.**
* Make sure your pan is at least 3" deep.
** The cooled lemon syrup can be drizzled over cake or used in various beverages. I used mine in homemade iced tea.Madeira Cake recipe adapted from Nigella Lawson.
Candied Lemon recipe from Our Best Bites