The fact is that hush puppies are a fried cornmeal dumpling, whether you've heard of them or not;
your familiarity with them is totally irrelevant to the truth of that proposition.
This kind of parenthetical clause (there are a lot of kinds, because there are lots of uses for parentheses) modifies the performative predicate, indicating the reason for the speaker's mentioning the definition; as Jim McCawley might put it, it refers to the act of informing the addressee that hush puppies are a fried cornmeal dumpling, rather than to the truth of the proposition that hush puppies are a fried cornmeal dumpling.
Here's some discussion by McCawley on the topic:
When people speak, they are not merely constructing a sequence of propositions but are performing actions of a wide variety of types: informing, reminding, requesting, challenging, offerring, and so on. These acts generally involve propositions but must be kept distinct from the propositions that they involve; for example, the proposition that Lima is further east than Miami is distinct from an act of reminding someone that Lima is further east than Miami or of reminding someone that Lima is further east than Miami.
The notions of truth and falsehood are strictly speaking applicable only to propositions, not to speech acts. In discussing the content of propositions it is necessary to refer both to propositions and to speech acts. Consider, for example, the following two dialogs:
A: The moon is owned by General Motors.
B: That's false.
A: Your father is a retired pimp.
B: That's pretty damn cheeky of you.
In (1), that refers to the proposition that A has just asserted. In (2), that refers to the act that A has just performed, that is, the act of telling B that B's father is a retired pimp, and not to the proposition that B's father is a retired pimp.
- from McCawley 1993, Everything that Linguists have Always Wanted to Know about Logic* (*but were ashamed to ask) 2nd ed, Chapter 9 "Speech Acts and Implicatures", p 290.