Melt butter: Heat your skillet over medium-low heat and add the unsalted butter. Stir gently until it melts and turns a lovely amber color—this should take about 2-3 minutes.

Mix sugars: In the warm skillet, combine the brown sugar and granulated sugar. Stir until the mixture is smooth and combined, then let it cool for a few minutes.

Add egg and vanilla: Once the mixture has cooled slightly, add the vanilla extract and crack in the large egg. Stir until everything is beautifully combined and smooth.

Combine dry ingredients: In a separate bowl, whisk together the all-purpose flour, baking soda, and salt. Fold this dry mixture into the wet mixture until just incorporated, being careful not to overmix.

Fold in mix-ins: Gently fold in the white chocolate chips and pink jimmies sprinkles. If you’re feeling extra festive, toss in the optional Valentine’s Day M&M's for a splash of color.

Bake: Spread the dough evenly in the skillet, smoothing it out. Pop it into the preheated oven at 350°F and bake for 15-18 minutes, until the edges are golden brown and the center is just set.

Cool and serve: Remove from the oven and allow the cookie to cool for a few minutes. Top with a generous scoop of vanilla ice cream or fresh berries for an extra treat before serving!