Place the softened Land O'Lakes unsalted butter, Domino granulated sugar, and C&H light brown sugar into a large clear glass mixing bowl. Use an electric hand mixer on medium speed (about 5 on a 10-dial) to beat the ingredients together for exactly 3 minutes. Scrape the bowl down with a spatula halfway through to make sure everything incorporates evenly. You will see the mixture transform from dense yellow lumps into a fluffy pale-ivory paste. The grainy sugar crystals will mostly dissolve into the fat and you will hear the mixer motor ease up as the mixture aerates. (I tried using cold butter the first time and it just chased the sugar around the bowl, room temperature at 68°F is the fix.) Miss this window and the cookies will turn out dense and heavy instead of tender. Beat on medium speed for 3 minutes, creaming traps vital air pockets that help the dough rise.

Add the large Eggland's Best egg, Jif creamy peanut butter, and McCormick vanilla extract directly into the creamed butter mixture. Turn the hand mixer to low speed and blend for about 60 seconds until the liquid is fully absorbed. Do not overmix here because you do not want to whip too much air into the eggs. The pale creamed base will quickly turn into a smooth uniform tan batter. The distinct smell of roasted peanuts and sweet vanilla will fill the air as the blades combine the fats and emulsify the liquid egg into the sugar base. Go past 60 seconds and the egg proteins will tighten up and make the final cookie tough. Blend on low speed just until uniform, gentle mixing keeps the delicate emulsion stable without overworking the egg.

Sift the Great Value all-purpose flour, Arm and Hammer baking soda, and Morton kosher salt directly over the wet batter. Use a stiff silicone spatula to fold gently with a rubber spatula in a J-shaped motion, cutting down through the middle and sweeping up the sides. Mix for about 90 seconds until no white streaks remain. The wet batter will pull the dry flour in and form a thick tacky dough that aggregates into a large mass. You will see small uneven clumps form at first, but they will quickly merge into a cohesive beige dough that pulls away cleanly from the sides of the glass bowl. Skip the gentle fold and use a mixer instead and you will develop too much gluten. Fold gently by hand for 90 seconds, manual mixing prevents a tough texture by limiting gluten activation.

Scoop out tablespoon-sized portions of dough and roll them between your palms into smooth round spheres. Place them onto an ungreased aluminum sheet pan, spacing them exactly 2 inches apart to allow for spreading. You should have 25 round dough balls arranged in an alternating layout across the tray. You will see uniform beige spheres with a slightly matte surface resting on the shiny metal tray. The dough will feel pliable and slightly oily from the peanut butter, holding its round shape perfectly without slouching or sticking to your hands. Leave uneven spacing and the cookies will merge into one giant block during baking. Space the dough spheres exactly 2 inches apart, proper layout ensures hot air circulates evenly around each cookie.

Slide the aluminum sheet pan into a 350°F preheated oven and bake for exactly 10 to 12 minutes. Do not open the oven door during the first 8 minutes because a sudden draft can halt the rising process. Remove the pan immediately when the timer sounds. The edges turn deep golden and a thin crust forms on the surface while the centers look slightly soft and puffed. You will smell a rich aroma of toasted sugar and roasted peanuts drifting from the oven right when the cookies are ready. Go past 12 minutes and the bottom scorches from the direct heat of the metal pan. Bake at 350°F for 10 to 12 minutes, moderate heat sets the outer rim while keeping the center tender.

Let the cookies cool on the tray for exactly 5 minutes, then press an unwrapped Reese's Mini Peanut Butter Cup upside down into the center of each soft cookie. Press firmly enough to imbed the chocolate but do not push all the way through to the bottom. The hot cookie will immediately start to melt the edges of the chocolate cup, creating a secure bond. You will see the cookie center indent and crack slightly around the edges of the chocolate candy, creating a rustic homemade look. (My first batch was too hot and the chocolate melted into a puddle, waiting exactly 5 minutes is the secret.) Press too early and the chocolate melts entirely into an unappealing brown smear. Wait exactly 5 minutes before pressing, gentle cooling keeps the chocolate structural integrity intact while binding it.

Let the cookies cool completely for 20 minutes until the chocolate firms up. Use a small plastic piping bag filled with melted black cookie icing to dot two small spots on the chocolate cup and press the candy eyes into place. Then pipe eight small jointed legs extending outwards onto the cookie surface, starting from the chocolate base. You will see cute spooky spiders emerge as the white candy eyes pop against the brown chocolate and the glossy black icing legs freeze into place. The final cookies look beautifully hand-crafted with charming imperfections and natural spacing. Decorate while the cookie is warm and the icing will run into a messy black blur. Cool completely before piping details, a cold surface ensures the icing lines stay sharp and distinct.