1-First Step: Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper. This prevents sticking and ensures even baking. Measure out all dry ingredients like flour, baking powder, baking soda, and salt into a bowl; whisk together for quick mixing later.

2-Second Step: In a large mixing bowl, beat the softened butter, granulated sugar, and brown sugar on medium speed until light and fluffy, about 2-3 minutes. Scrape down the sides to incorporate everything fully. This creaming process traps air for tender cookies.

3-Third Step: Add the crunchy peanut butter, eggs, and vanilla extract to the butter mixture. Beat until smooth and fully combined, around 1 minute. The mixture should look glossy and uniform.

4-Fourth Step: Gradually add the dry ingredients to the wet mixture on low speed. Mix just until a dough forms; do not overmix to keep the crunch. The dough will be soft but scoopable.

5-Fifth Step: Scoop tablespoon-sized portions of dough and roll into balls. Place them 2 inches apart on the baking sheets. Use a fork to press each ball twice, creating the classic crisscross pattern and flattening to about 1/4-inch thick. This step enhances the crunchy texture.

6-Sixth Step: Bake for 10-12 minutes until edges are golden brown. Cookies will firm up as they cool. Let them rest on the sheet for 5 minutes before transferring to a wire rack. Cool completely before filling, about 30 minutes total.

7-Seventh Step: While cookies cool, prepare the filling. Beat softened butter, creamy peanut butter, powdered sugar, milk, and vanilla on medium speed until creamy and spreadable, 2-3 minutes. Taste and adjust milk for desired thickness.

8-Eighth Step: Spread or pipe about 1 tablespoon of filling onto the flat side of half the cooled cookies. Top with remaining cookies, pressing gently to sandwich. Makes about 24 sandwich cookies.

9-Final Step: Store in an airtight container. Enjoy immediately for maximum crunch or let sit overnight for flavors to meld. These nutter butter cookies recipe treats shine at room temperature.