Line baking sheets with parchment paper or silicone baking mats to prevent sticking and caramel burning. Preheat your oven to 350°F (175°C). Make sure butter and eggs are at room temperature.

In a medium bowl, whisk together the flour, cornstarch, baking soda, baking powder, and fine sea salt until well combined and no clumps remain.

In a large mixing bowl using a stand mixer with paddle attachment or a handheld mixer, beat the softened butter, packed light brown sugar, and granulated sugar on medium speed for 2–3 minutes, until light, fluffy, and slightly paler in color.

Add the eggs one at a time, beating well after each addition and scraping down the sides of the bowl as needed. Mix in the vanilla extract just until combined without overmixing.

With the mixer on low speed, gradually add the dry ingredient mixture to the wet ingredients. Mix just until no streaks of flour remain; the dough should be thick, soft, and slightly sticky. If using mini chocolate chips, nuts, or cinnamon, gently fold them in with a spatula. If the dough is very sticky, add 1–2 tablespoons of extra flour sparingly.

Cover the bowl with plastic wrap or a lid and chill the dough in the refrigerator for at least 30–45 minutes, and up to 48 hours. Chilling helps develop flavor, keeps the cookies thick, and helps prevent the caramel from leaking. If chilled more than 2 hours, let the dough sit at room temperature for 10–15 minutes before scooping.

Using a medium cookie scoop (about 1 1/2 tablespoons of dough), portion the chilled dough. Flatten each portion gently in your palm and place one soft caramel candy in the center. Wrap the dough completely around the caramel, pinching seams closed so there are no gaps, then roll into a smooth ball. Arrange on prepared baking sheets, spacing about 2 inches apart. If caramels are very firm, briefly microwave them for 5–7 seconds to soften slightly before wrapping.

Bake one sheet at a time at 350°F (175°C) for 10–12 minutes. The cookies are done when the edges look set and lightly golden but the centers are still soft and slightly puffy; they will continue to cook on the hot pan after you remove them from the oven. For perfectly round bakery-style cookies, immediately after baking use a large round cookie cutter or the rim of a glass to gently scoot around each cookie to nudge it into a circle. If making salted caramel cookies, sprinkle a pinch of flaky sea salt on top while the cookies are still warm.

Let the cookies cool on the baking sheet for at least 10 minutes; the caramel will be extremely hot at first. Transfer to a wire rack to cool completely, or serve slightly warm for the gooiest caramel center.

Store completely cooled cookies in an airtight container at room temperature for 3–4 days, layering with parchment if stacking. To soften and re-goo the caramel, microwave a cookie for 8–10 seconds before serving.

For longer storage, freeze cooled cookies in a freezer-safe container or bag for up to 2 months. Thaw at room temperature, then warm in the microwave for 10–12 seconds for a melty caramel center.

To freeze unbaked cookies, shape dough around the caramels and place on a parchment-lined tray. Freeze until solid, then transfer to a freezer bag or container. Bake from frozen at 350°F (175°C), adding 1–2 extra minutes to the bake time as needed.