Can you substitute corn starch for flour in crumb topping?

You can substitute cornstarch for flour in a crumb topping, but it will result in a denser, crispier, and less crumbly topping. Here's why and some tips for successful substitution:

Why Cornstarch Changes the Texture:

* Less Gluten: Cornstarch is gluten-free, unlike wheat flour. Gluten creates the "crumbly" texture in a topping.

* Higher Absorption: Cornstarch absorbs more moisture than flour, resulting in a firmer, less crumbly consistency.

Tips for Using Cornstarch in Crumb Topping:

1. Reduce the Amount: Start with half the amount of cornstarch as you would flour. This will give you a slightly crumbly texture, but still maintain the crispiness.

2. Increase the Fat: Adding more butter or margarine to your cornstarch topping will help offset the denser texture and make it more crumbly.

3. Experiment: Taste and adjust the amount of cornstarch and fat until you achieve the desired texture.

4. Use Cold Ingredients: Cold butter and cornstarch will prevent the topping from becoming too sticky.

Alternative Option:

For a closer substitute to flour in a crumb topping, you can use all-purpose flour with a high protein content. This will produce a slightly more crumbly topping than cornstarch.

Final Thoughts:

Using cornstarch in crumb topping will change the texture, but it can still be a delicious and satisfying option. You might enjoy the crispier texture if you prefer a less crumbly topping.