Learn Dutch: Dit kruidige gerecht laat zich snel bereiden. - This spicy dish can be prepared quickly.

The construction zich laten + a bare infinitive is used to express that something can be done to the subject. It is a way to express a passive possibility without using kunnen and worden. Literally, it says the dish "lets itself prepare," but in natural English, it means it "can be prepared."

Could I use a normal passive sentence here, like ... kan snel bereid worden?

Yes, Dit kruidige gerecht kan snel bereid worden is grammatically correct and means the exact same thing. However, using laat zich is a very natural and slightly more elegant way to express this in Dutch, especially in written text or when describing the inherent qualities of an object.

Since gerecht is a het-word, shouldn't the adjective drop the -e and be kruidig?

You only drop the -e for a singular het-word when it is indefinite (like after een, geen, or nothing at all). Because we are using the definite demonstrative pronoun dit (this), the adjective gets the standard -e ending: dit kruidige gerecht. If it were "a spicy dish," it would be een kruidig gerecht.

Why use bereiden here instead of voorbereiden?