Preheat your oven to 325°F (165°C). Grease and flour a 10-inch bundt pan or a 9x5-inch loaf pan thoroughly.

Make sure your butter and eggs are at room temperature.

Sift the flour, baking powder, and salt together into a bowl.

In a large mixing bowl, beat the softened butter on medium speed for about 2 minutes until creamy and pale.

Gradually add the sugar and continue to beat for 4–6 minutes until light and fluffy.

Add the eggs one at a time, beating briefly after each addition.

Mix in the vanilla, lemon zest, lemon juice, and sour cream (if using).

With the mixer on low, alternate adding the dry ingredients and the warmed milk in three parts: flour, milk, flour — beginning and ending with flour. Mix just until combined.

Pour the batter into the prepared pan, smoothing the top with a spatula.

Bake in the preheated oven for 70–90 minutes for bundt, or 60–75 minutes for loaf.

Let the cake cool in the pan on a wire rack for 15–20 minutes, then invert onto the rack to cool completely.

For an extra glossy top, brush with a simple glaze while warm.

Slice with a serrated knife for clean edges and serve slightly warm or at room temperature.