Heat the oven to 350 F. Combine the crushed pretzels, brown sugar and melted butter, then press the mixture firmly into the bottom and sides of a 9-inch pie plate.
Bake the crust for 10 to 12 minutes, until fragrant and lightly toasted. Cool completely.
Heat the cream for the ganache until steaming and pour it over the chopped chocolate. Let it stand for 2 minutes, stir until smooth and spread over the cooled crust. Refrigerate for 20 minutes.
Beat the cream cheese, peanut butter, powdered sugar, vanilla and salt until smooth. In a separate bowl, beat the heavy cream to medium peaks.
Fold one-third of the whipped cream into the peanut butter mixture, then gently fold in the remainder. Spread the filling over the firm ganache and refrigerate for at least 6 hours.
Beat the topping cream and powdered sugar to firm peaks, then spoon or pipe it over the chilled pie. Arrange the mini pretzels on top.
Melt the semisweet chocolate with the coconut oil and cool for 5 minutes. Drizzle it over the pie shortly before serving so the pretzels remain crisp.