"I eat a pepper steak."
Translation:Io mangio una bistecca al pepe.
When talking about food:
di xyz - it's made of xyz
con xyz - it contains or includes xyz as a side dish
al xyz - it is flavoured with XYZ (to the taste of XYZ)
succo di arancia = juice of orange ~ 100% orange juice
succo con arancia = juice with orange ~ fruit juice with orange
bistecca con patata / panino con formaggio e prosciutto
succo al arancia = juice to the orange ~ orange flavoured juice (can even be artificial flavour)
First of all, in all latin languages like Italian or Spanish, you use adjetives after nouns instead of, as in English, you put all adjetives before nouns.
On this case, "al pepe" is modifying the noun directly. If you put "I eat steak" the translation is "Mangio una bistecca", to being specific of the taste of the stake you put "pepper steak", that means "bisteccca al pepe" in Italian and "bistec a la pimienta" in Spanish.
What's the difference between 'I eat a pepper steak' and 'I eat a steak pepper'? The former means that you are eating a steak that tastes of pepper, the latter that you are eating a pepper with the taste/made of/in a steak.
English uses the word order to establish a relationship between words. In Italian you cannot do that; you need to use prepositions that expose/clarify what one word is to another, exactly as in ' a steak with the taste of pepper'.
I'm not sure which variety of English you're talking about. In the USA, there's no such thing as a "steak pepper". A "pepper steak", especially in the Boston area, is a sandwich made with strips of beef and bell peppers. So "I eat a pepper steak" would be "Mangio un panino con bistecca e peperoni".