A stranger at a bake sale made me admit I was overmixing muffin batter
I spent all summer making dense, hockey puck muffins and thought it was the recipe. A lady buying lemon poppyseed at our church sale in Portland took one bite and said 'you killed the gluten, hon.' I got defensive but looked it up that night. She was right. I was beating the batter until smooth for like 2 straight minutes. Now I stir until just combined, maybe 12 turns tops, and lumps are fine. Next batch came out actually fluffy. Has anyone else completely missed something this basic for way too long because no one told you straight?
Oh man, hate to say it but the gluten thing is a little off. Gluten actually gets stronger the more you mix it, so all that beating is what made them tough, not "killed" it. That lady was right about the fix though, you just had the science backwards.