01 - Preheat your oven to 350°F. Grease and flour a 9-inch round cake pan, or line with parchment paper.
02 - In a medium bowl, whisk together the flour, baking powder, and salt until well blended.
03 - In a large bowl, beat the butter and sugar together until light and fluffy, about 2-3 minutes.
04 - Add eggs one at a time, mixing well after each addition. Stir in the vanilla extract and lemon zest, if using.
05 - Gradually add the dry ingredients to the wet mixture, alternating with milk, beginning and ending with the dry ingredients. Mix until just combined.
06 - Gently fold in the raisins until evenly distributed throughout the batter.
07 - Pour the batter into the prepared pan and smooth the top with a spatula.
08 - Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
09 - Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
10 - Dust with powdered sugar before serving. For extra flavor, serve with butter and jam.