Start by preheating your oven to 350°F (175°C). This sets the stage for baking, allowing your cookies to rise perfectly and develop a lovely golden color.

Line your baking sheets with parchment paper. This will prevent the cookies from sticking and ensures an easy release once they're baked. You can also use silicone baking mats to achieve a similar effect.

In a large bowl, combine the softened unsalted butter, granulated sugar, and dark brown sugar. Beat it with an electric mixer on medium speed until the mixture is creamy. This usually takes about 2 minutes. Scrape down the sides occasionally to ensure everything is well combined.

Next, it’s time to add in the creamy peanut butter. Blend it into the sugar mixture until smooth. After that, mix in the Greek yogurt or sour cream, egg, and egg yolk. Don’t forget the vanilla extract! It adds that lovely aroma and flavor we all love so much.

In another bowl, whisk together the all-purpose flour, baking soda, baking powder, sea salt, and ground cinnamon (if using). Gradually add this dry mixture to the wet ingredients. Mix on low speed until just combined. Be careful not to over-mix; this will keep your cookies soft.

Using a spatula, gently fold in the chocolate chips and chopped roasted peanuts, if you’re using them. This adds a delightful crunchy texture to the cookies.

Using a tablespoon or a cookie scoop, drop rounded balls of dough onto your prepared baking sheets. Leave enough space between each cookie; they will spread as they bake.

Place the baking sheets in the preheated oven and bake for about 10-12 minutes, or until the edges are lightly golden. Make sure not to overbake! You want them soft in the middle.

Allow the cookies to cool on the baking sheets for about 5 minutes before transferring them to wire racks to cool completely. Don’t skip this step—this is where the magic happens, and they set up perfectly.