MELT BUTTER: Start by melting the butter in a microwave-safe bowl. Once melted, set aside to cool for 5 minutes. (Hot butter will cause a greasy crust.) If you will be baking the crust, preheat the oven to 350 degrees F (175 degrees C).
BLEND OREOS: In a blender or food processor, process the FULL cookies (don't separate cookie from cream) until they are all fine crumbs (re-blend any large chunks). Measure to get a level 1 and 3/4 cups of crumbs (Note 2) and add to a large bowl.
MIX: Add in the salt. Use a spatula to scrape every bit of the melted and cooled butter into the bowl. Gently stir with a wooden spoon until well combined. Spread the mixture into the prepared pan.
PRESS TOGETHER: Using your fingers, press the crumbs into the bottom of the pan and then up the sides. Use the bottom of a flat 1-cup measuring cup to thoroughly compress the Oreo crumbs into a firm crust.
BAKE OR CHILL: To bake: Place in the preheated oven for 10 minutes and set aside to cool or chill the crust. (If baking, allow the crust to fully cool before adding the filling.) To chill: Cover the formed crust tightly and freeze for 10 minutes or refrigerate for 20 minutes before filling to allow time for the crust to firm up and butter to re-solidify.
STORAGE: This crust is best used the same day it's made, but it can be baked up to 1 day ahead and stored, tightly covered, at room temperature. Don't store an unbaked crust, uncovered, for more than a few hours -- it will start to dry out and can become crumbly.
Notes
Note 1: Oreos: While it’s easiest to just add Oreos to the blender, there can be a good amount of variation from cookie to cookie and brand to brand. Measure the crumbs instead of only counting out cookiesNote 2: Measuring: Slightly overfill the measuring cups and then level off the top with the back of a table knife for the perfect measurement.Note 3: Scaling up the recipe: The way you make this crust is the same from dessert to dessert; the only things that will change are quantities depending on pan size and whether you need to bake or chill the crust.