In what type of food can nuts often be a hidden ingredient?

Nuts can often be a hidden ingredient in various types of food due to their versatility and the wide range of cuisines that utilize them. In Indian curry paste, for example, nuts such as cashews are frequently ground into the paste to add creaminess and enhance flavor. This use is not commonly recognized, so it can be a surprising allergen for those with nut allergies.

In the case of burgers, nuts might be included in certain forms or versions like nut-based patties or as part of seasoning blends. While it is less common in traditional meat burgers, there are many vegetarian or vegan variants that incorporate nuts for texture and protein content.

Pastry can also contain nuts, often in the form of ground nuts in the dough or as a filling, such as almond paste or hazelnut spread. Pastry items can therefore conceal nuts in a variety of ways, making them another area of concern for individuals with allergies.

Given the diversity of these three food categories, stating that nuts can be a hidden ingredient in all of them reflects the reality that nuts are present in a multitude of culinary applications. Thus, this reasoning supports the selection of the answer that encompasses all the mentioned foods.