Position a rack in the center of the oven and heat the oven to 190°C (375°F).
Process the wafers/biscuits until fine crumbs (there should be about 2 cups-ful).
In a medium bowl, stir together the crumbs and melted butter until the crumbs are evenly moist and clump together slightly.
Transfer the mixture to a greased 8 or 9 inch springform pan and press evenly onto the bottom, spreading any remainder up the sides.
Bake until the crust is fragrant and slightly darkened, 9 to 12 minutes. Let the pan cool on a rack. Lower the oven temperature to 150°C (300°F).
In a stand mixer fitted with the paddle attachment, beat the cream cheese, crème fraîche, flour, and salt on medium speed, scraping down the sides of the bowl and the paddle frequently, until very smooth and fluffy, about 5 minutes. Make sure the cheese has no lumps (if you find there are lumps at the end, you can always strain through a sieve).
Add the 1-1/4 cups granulated sugar and continue beating until well blended and smooth.
Add the vanilla and instant espresso powder and beat until blended, about 30 seconds.
Add the eggs one at a time, beating just until blended (don’t overbeat once the eggs have been added or the cheesecake will puff too much and crack as it cools.)
Pour the filling into the cooled crust and smooth the top.
Bake until the center jiggles like jelly when nudged, 55 to 65 minutes. The cake will be slightly puffed around the edges, and the center will still look moist.
Set on a rack and cool completely.
Cover and refrigerate until well chilled, at least 8 hours and up to 3 days.