How to make crispy crepes? I make very thin crepes using batter made of 500 grams of flour, 3 eggs and 250 ml of milk. They turn out thin, soft and pliable. My wife on the other hand remembers fondly her mothers crepes, which used to be a bit thicker and had a bit of crunch.

How should I modify my recipe or technique to make them more like that? I'm guessing using more fat (I try to use as little as possible) could help, but then I run into problems spreading the batter over the pan surface.
A crisp crepe is less about the recipe and more about the cooking technique. You simply need to leave it a little longer before flipping it, allowing the edges to crisp. A little more oil than usual will help, but it should still only be a thin coating wiped on with a paper towel.

To make a thicker crepe, simply use less liquid. You can also look at using alternative flours like buckwheat which alter the texture.