Learn French: Cette pâtisserie fait de très bons gâteaux.

Normally, "some cakes" would be des gâteaux. However, there is a special rule in French: when a plural adjective (like bons) comes before a plural noun, the plural article des changes to de. Since très bons comes before gâteaux, we use de instead.

Why does the adjective bons come before the noun gâteaux instead of after it?

Most French adjectives come after the noun, but short, common adjectives that describe Beauty, Age, Number, Goodness, or Size (often remembered by the acronym BANGS) usually come before the noun. Since bon (good) describes "Goodness", it goes before gâteaux.

Does pâtisserie mean "pastry" or "cake shop"?

It means both! In French, une pâtisserie can refer to a specific pastry you eat, or the bakery where those pastries are sold. In this sentence, the context tells us it is the shop itself making the cakes.

Could I use the verb préparer or cuisiner instead of faire here?

You will sometimes hear préparer, but faire is the most natural and common verb to use when talking about making or baking cakes (faire un gâteau). Cuisiner generally refers to cooking savory meals rather than baking.