I wouldn’t exactly call them hot pads, or hot mitts, these are “pot grabbers”, and made to fit my little kitchen helpers’ eager hands.
Cotton yarn is important, to prevent melting yarn. I don’t know if a cotton blend would be fine, so I always go 100% cotton. (Peaches & Cream is the brand I’m using, if that matters to you.)
Using a J hook, Chain 20, turn and single crochet 11 rows in a continuous spiral, so you have a sort of envelope shape. Collapse into a “magic square” (tutorial here) and repeat 3 times to make 3 “magic squares” of equal size.
Fold the middle square in half and attach half of the middle square to each of the other squares to create that grabber shape.
Chain 8-10 stitches after you’ve single crocheted those squares together, and make a loop by attaching that chain back to the piece in the original spot, single crochet along that chain to crate thickness, cut that yarn and weave in the in the ends. My 6 year old brought me a hot pan with this just this evening, so I’d call that thickness a win!