If you made a batch of muffin that came out the oven with strange knobby shapes what would expect to be reason?

One reason for strange 'knobby' shapes could be an incorrect ratio of baking powder or baking soda. Too much or too little of either can cause muffins to rise unevenly and form protrusions. Check the recipe and make sure you measured the baking powder or baking soda correctly.

Mixing Method:

Over-mixing the batter can lead to the development of gluten in the flour. This can result in a tough texture and knobby shapes in the muffins. Gently mix the ingredients just until combined to avoid over-development of the gluten.

Oven Temperature:

An incorrect oven temperature can also contribute to uneven rising. If the oven is too hot, the muffins may rise quickly and unevenly, forming knobby shapes. Make sure to preheat your oven to the specified temperature and place the muffin pan in the center of the oven for even baking.

Levain:

If you used a levain (natural yeast) in your muffin recipe, it could be the culprit behind the unusual shape. Levain can create a more rustic and uneven rise, resulting in knobby formations in the muffins. This characteristic is often considered part of the charm of yeast-based baked goods.

Ingredient Quality:

The freshness of your ingredients, especially the baking powder or baking soda, can impact the rising process. Old baking powder or baking soda may not be effective, leading to uneven rising and knobby shapes. Make sure to use fresh ingredients for best results.

If you address these potential causes, your next batch of muffins should rise more uniformly and come out with a more pleasing shape.