Where do I get 3 1/2 x 1 3/4 muffin liners?

Question

Super jumbo muffin liners

Answer 1

If you cannot find liners that size you could always lightly grease then flour the inside of the pan. After flouring, turn the pan over and tap to get rid of excess flour.
or
You could use parchment paper to make your own liners.

Answer 2

You don't . Taking baking paper, lay on the backside of the tin, draw the form of the back and cut it out. Butter the tin, place the paper in and your dough and bake.

Good luck!