Heat oven to 350 degrees F (175 degrees C). Grease and flour two 8 1/2- by 4 1/4-inch loaf pans, and line the bottoms with parchment paper. Alternatively, you can generously butter and flour a bundt pan.

Cream butter and 2 cups (400 grams) of the sugar (leave the last 1/2 cup for the syrup) in the bowl of an electric mixer fitted with a paddle attachment for about 5 minutes, or until light and fluffy. Mixing at medium speed, add eggs, one at a time, and lemon zest.

Sift together flour, baking powder, baking soda and salt in a bowl. In another bowl, combine 1/4 cup (60 ml) lemon juice, buttermilk and vanilla. Add flour and buttermilk mixtures alternately to butter and sugar mixture, beginning and ending with flour. Divide batter evenly between loaf pans or pour into prepared bundt, smooth top(s), and bake for 45 minutes to 1 hour, until a cake tester comes out clean. The bundt version tends to be done in 45 to 50 minutes.

Make soaking syrup: Combine remaining 1/2 cup sugar with 1/2 cup lemon juice in a small saucepan, and cook over low heat until sugar dissolves.

When cakes are done, let them cool 10 minutes. Invert them onto a rack set over a tray, and spoon lemon syrup over cakes. Let cakes cool completely.

Make the glaze: Combine confectioners’ sugar and remaining 3 1/2 tablespoons lemon juice in a bowl, mixing with a whisk until smooth. Pour over top of cakes, and allow glaze to drizzle down the sides.