Prepare your oven and workspace. Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper. This prevents sticking and ensures even baking.
Combine the dry ingredients. In a medium bowl, whisk together the flour, baking soda, baking powder, and salt until well incorporated. Proper mixing now prevents flour pockets in your finished cookies.
Cream butter and sugar. In a large bowl, beat the softened butter and 1½ cups sugar with an electric mixer on medium speed until light and fluffy, about 3-4 minutes. Don’t rush this step – proper creaming creates the perfect texture.
Add wet ingredients. Beat in the egg until combined, then mix in vanilla extract, lemon zest, and lemon juice. The mixture might look slightly curdled, but this is normal.
Combine wet and dry mixtures. Gradually add the dry ingredients to the wet ingredients, mixing on low speed just until combined. Overmixing will develop gluten and make tough cookies.
Chill the dough. Cover the bowl and refrigerate for at least 30 minutes. This prevents excessive spreading and intensifies the flavor.
Shape the cookies. Place the remaining ¼ cup sugar in a small bowl. Roll the chilled dough into 1½-inch balls, then roll each ball in the sugar to coat completely.
Arrange on baking sheets. Place the cookie balls on the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
Bake to perfection. Bake for 8-10 minutes, just until the edges are set but the centers still look slightly underdone. They will continue cooking on the hot baking sheet.
Cool properly. Let the cookies cool on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely. If using the optional lemon-sugar coating, dust it over warm cookies.