As in the title, what's your protein sludge recipe? I didn't know it was so popular until I just read through the "how much protein do you supplement" thread. I need some ideas.
I either use a low carb Greek yogurt (unflavored), sometimes a low carb flavored one as the base then add in some whey protein. You need to mix whey with something other than just liquid or ir will just be a watery chunky mess. Cheaper whey or whey+ blend will be easier to turn into sludge.
If not yogurt then I use unsweetened almond milk, mix some plant protein with whey (can also use micellar casein but I think plant protein works way better). Other options is to add a big heaping tablespoon or 2 of powdered peanut butter (which is a plant protein) to your whey and that will make for a good sludge consistency.
Start with 4oz liquid then add powder then slowly add more liquid as needed until its the consistency you want.
Lately I've been mixing 1 heaping scoop of chocolate brownie batter plant protein and 2 scoops peanut butter cookie flavor whey protein isolate with unsweetened vanilla almond milk, eat with spoon. It's like eating a Reese's peanut butter cup. It's like a treat and I have it every day. I haven't had a "shake" in decades.
I sometimes throw in a handful of some protein puffs as well for added crunch and protein.