Wiktionary
mind you
phr. 1 (label en idiomatic colloquial chiefly UK) (non-gloss definition: Used to draw attention to a part that is important to a statement.) 2 (label en literally archaic) Mind that you; be careful that you.
Usage examples of "mind you".
Fasten one end to that sturdy-looking pipe, securely mind you since it is a long drop.