I thought Pfuel was a silly (foolish) made-up name. But actually this is another real historical person. Karl Ludwig von Phull may have been the one who thought up the “scorched earth retreat”. (The German wikipedia adds the useful comment that this tactic was already current having been used successfully against Napoleon in 1808 in Spain.)
Russian wikipedia has a detailed article on the reinforced encampment at Drissa, which is now the Belarusian town of Verkhnyadzvinsk near the border with Latvia.