Bring eggs, peanut butter, and butter to room temperature before mixing to ensure smooth blending and prevent lumps in your batter, resulting in a perfectly fudgy texture.

Mix the dry ingredients until just combined after adding eggs—overmixing incorporates excess air and leads to cakey brownies instead of the desired dense, gooey fudge-like consistency.

Drop peanut butter mixture in spoonfuls across the chocolate batter, then use a knife to drag through gently in one direction for beautiful, even swirls without over-blending the flavors.

Remove brownies when a toothpick inserted in the center shows just a few moist crumbs—they'll continue cooking as they cool, ensuring fudgy centers rather than dry, overbaked brownies.

Melt chocolate chips and cocoa powder together with butter to create a smooth, rich base that fully incorporates and prevents grainy texture in your final brownies.