Spreading and flattening of cookie dough is a common frustration that many home bakers face when baking cookies. The final cookies often turn out much wider and thinner than desired, losing their defined edges and becoming one giant cookie. Luckily, there are a few simple tricks to prevent cookie spread so you can achieve beautifully shaped, bakery-style cookies at home.
What causes cookie dough to spread?
There are a few main culprits when it comes to cookie spread:
- Too much butter or oil – Fat content causes cookies to spread by greasing the baking sheet. Using excessive amounts of butter or oil can lead to a flattened cookie.
- Overmixing – Overmixing the dough develops too much gluten, causing cookies to lose their shape and spread.
- High oven temperature – Baking cookies at too high of a temperature causes the dough to spread before setting.
- Too much raising agent – An overload of baking soda or baking powder leads to over-rising and spread.
By adjusting these factors, you can prevent cookie dough from spreading too much in the oven.
How does cornstarch prevent cookie spread?
Using cornstarch is one of the most popular and effective ways to stop cookie spread. Here’s how it works:
- Cornstarch absorbs moisture – Excess moisture causes cookie dough to spread. Cornstarch soaks up some of the moisture, keeping the dough firmer.
- Thickens the batter – Adding cornstarch gives more structure to the cookie dough, making it thicker so it holds its shape better.
- Less gluten formation – Overworking gluten leads to spreading. Cornstarch dilutes gluten development from the flour.
- Adds density – The addition of cornstarch makes cookie dough denser, preventing it from becoming too thin.
Overall, cornstarch acts as a thickening agent to create sturdier cookie dough that resists flattening and retains its shape during baking.
How much cornstarch should you add?
The amount of cornstarch you need to stop cookie spread will depend on the cookie recipe, but a good guideline is:
- 1-2 tablespoons cornstarch per 1 cup (125g) of flour
Start with 1 tablespoon and add more as needed if cookies are still spreading too much. Be careful not to exceed 2-3 tablespoons cornstarch per 1 cup flour as too much cornstarch can leave a chalky texture.
Should you replace flour with cornstarch?
It’s best to add cornstarch in addition to the flour in a cookie recipe rather than substituting it for flour. Here’s why:
- Flour provides structure – Replacing flour with cornstarch makes cookies too delicate.
- Impacts flavor – Flour contributes to cookie flavor, while cornstarch is purely for texture.
- Too much starch – Swapping all-purpose flour for cornstarch throws off the starch ratio.
- Gluten development – You need the gluten from flour for cookies to set up properly.
Substituting small amounts of cornstarch for flour is okay, but for best results, keep flour in the recipe and add cornstarch as extra insurance against spreading.
What other ways prevent cookie spread?
While cornstarch is excellent for preventing cookie spread, you can also try these tricks:
- Chill dough – Chilling dough for at least 2 hours firms up the butter so cookies hold shape.
- Use cake flour – Lower protein cake flour develops less gluten to minimize spread.
- Reduce fat – Cut back on butter or oil slightly if your recipe is very high fat.
- Don’t overmix – Gently combine wet and dry ingredients without over-beating.
- Lower oven temp – Bake at 300-325°F instead of 350°F to set dough before spreading.
- Use parchment paper – Lined sheets prevent sticking to pan edges causing spread.
Does cornstarch work for all cookie recipes?
Cornstarch is a handy addition to most cookie recipes, but works best in certain types of cookies:
| Good for These Cookies | Avoid with These Cookies |
|---|---|
| Shortbread | Biscotti |
| Chocolate chip | Rolled sugar cookies |
| Oatmeal | Fortune cookies |
| Peanut butter | Icebox/slice-and-bake cookies |
| Sandwich cookies | Butter cookies |
In general, cornstarch works well for basic drop cookie recipes. Avoid using it for cookies that need to be rolled out or shaped.
Conclusion
Adding 1-2 tablespoons of cornstarch for every 1 cup of flour is an effective way to prevent cookie spread for soft, thick cookies that hold their shape in the oven. While replacing flour completely with cornstarch isn’t recommended, a small amount of cornstarch can give enough structure to cookie dough to stop it from becoming a flattened blob. Combined with chilling, parchment paper, and proper baking temperatures, cornstarch can help achieve picture-perfect cookies that look just as good as they taste.