In a medium bowl, whisk together the flour, baking soda, baking powder, and salt. Set aside.: You will notice a faint floury smell and a uniform pale mixture when the dry flour and leaveners are fully combined, which ensures even rise and prevents pockets of baking soda . Sifting is not required, but whisking breaks up clumps and aerates the mixture, helping the cookies stay light. A common mistake is mixing the leaveners directly into wet ingredients, which can cause uneven texture, so always combine them first and set them aside.
In the bowl of a stand mixer fitted with the paddle attachment or in a large mixing bowl, add the sugar and lemon zest. Using your fingertips, rub the zest into the sugar until the sugar is moistened and fragrant.: As you rub the lemon zest into the sugar , the aroma will erupt, giving citrus oils that perfume the sugar and infuse the entire cookie. The sugar will feel slightly damp and clumpy when the oils are released, a tactile clue that you have extracted enough flavor. Avoid overdoing the rubbing to prevent making the sugar too wet, which can alter creaming; a few dozen rubs are usually enough.
Using the stand mixer or an electric hand mixer, beat the butter into the lemon sugar until light and fluffy, 3-5 minutes. Add the egg, vanilla extract, and lemon juice and beat until well combined.: Once you add softened butter , the mixture will change from grainy to creamy, and you will hear the mixer shift to a smoother sound. After 3 to 5 minutes the texture should be pale and airy, which traps tiny air pockets for lift. When the egg , vanilla , and lemon juice are incorporated, the batter smells bright and buttery. A typical misstep is using cold butter , which prevents proper creaming and leads to dense cookies, so make sure it is softened but not melted.
Slowly add the dry ingredients, mixing just until combined.: As you fold in the dry mix, you will notice the dough change from glossy to slightly matte, and small streaks of flour should disappear quickly. This gentle mixing preserves tender crumb by avoiding overdeveloped flour proteins. Overmixing is a common pitfall that produces tough cookies, so stop as soon as the last streak of dry ingredient vanishes and the dough is uniformly colored.
Dollop the raspberry preserves in spoonfuls across the top of the dough, then use a rubber spatula to fold the preserves into the dough. Only fold the dough 3-5 times – you want to have streaks of preserves swirled into the dough, rather than mixing it in completely.: When you see vivid ribbons of raspberry against the pale dough, you will know you have folded just enough. The preserves will leave glossy streaks that look striking after baking. If you fold more than instructed, the preserves will fully blend into the dough and lose the attractive swirls, so be gentle and count your folds.
Use a 2 oz (4 tablespoon) scoop (ice-cream-scoop size) to scoop the dough onto a parchment-lined baking sheet. You can place the dough balls close together since they will not be going into the oven yet.: The dough will be dense and pillowy to the touch, and scooping creates uniform mounds that bake evenly. Positioning the scoop so some preserve swirls sit at the top helps achieve decorative tops after baking. A frequent error is making uneven scoops which bake inconsistently, so aim for consistent portions and wipe the scoop between uses if the dough sticks.
Place the baking sheet, uncovered, in the refrigerator to chill overnight or for at least 4 hours.: Chilling firms the butter and sets the shape, preventing excessive spread and encouraging those rounded, puffed centers. You will notice the dough cools and becomes easier to transfer; the preserves may thicken slightly. Rushing this step often leads to flat cookies, so be patient and give the dough adequate chill time.
When ready to bake, preheat the oven to 350°F. Place no more than 6 of the dough balls onto a lined baking sheet; keep the remaining dough balls in the refrigerator until ready to bake them.: As the oven heats the space will smell faintly of warm metal and anticipation, and the consistent heat ensures even browning. Limiting how many you bake at once avoids crowding and allows air to circulate for uniform edges. A common oversight is crowding the tray which causes uneven baking, so leave room between mounds.
Bake for 14-16 minutes, or until the edges are golden and the centers are puffed but still appear slightly underdone. Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack.: During baking you will hear a soft crackle and see edges take on a light golden color while centers remain slightly domed; that contrast signals a tender interior with set edges. Cooling briefly on the sheet allows carry over cooking to finish the centers without overbaking, and transferring to a wire rack prevents sogginess. Overbaking is the usual mistake here, which dries the cookie, so remove them when the centers still look a touch soft.