この文章が以下のように翻訳で決ます。
いつもあなたが食べている辛さで ー As spicy as you have it / As spicy as you would have it / as spicy as you always have / as spicy as you like it.
いつも ー Always / usually
あなたが食べている ー as you have it / as you eat
辛さで ー as spicy as
「Can I have it as spicy as you would have it」が一番ナチュラルです。
参考になれば嬉しいです。