Put mashed pretzels in an oven on warm. Melt the peanut butter morsels & white chocolate morsels together. (I do this on 50% power in the microwave for about 5 minutes, stirring at least once.)
When melted, mix in peanut butter, peanuts & the mashed pretzels.
Spread onto a WELL-greased 8×8 pan. (I always line the pan with parchment paper sprayed with Pam.)
Allow fudge to harden, about 2 hours. Cut in chunks. They are not meant to look perfect. DIG IN!