Preparation:
1. Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.
2. Whisk together flour, baking powder, baking soda, and salt.

Mixing:
1. Cream butter and sugars until light and fluffy.
2. Beat in eggs, vanilla, lemon zest, and juice.

Combining:
1. Gradually mix dry ingredients into wet ingredients.
2. Fold in white chocolate chips if using.

Baking:
1. Shape dough into balls and place on baking sheet.
2. Bake for 12-14 minutes until edges are golden.