A pastry chef has assembled a sheet pan with a silicon mat, an offset palette knife, a sheet of thin cardboard from a cake box, and a razor blade. You can assume that he or she is about to make cookies.

Stencil.

Explanation:

As per the question, the given description imply that the chef is making 'stencil' cookies as the sheets are assembled together in order to be cut in the desired shape(using stencil comprising of silicon mat and knife) and to be topped by the favorite ingredients. The assembled sheet pan along with a silicon mat would be cut in different shapes to get the desired cookie shape through the use of the offset palette knife, razor blade, and sheet of thin cardboard from the cake box. Therefore, this descriptions justify the deduction that the chef is making 'stencil' cookies.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.