Line a 9X5 loaf pan with plastic wrap (enough to hang over the sides so it's easier to remove later.
Place preserves in a mixing bowl and blend with a spoon until smooth.
Toast pecans over low heat in a skillet; cool and chop.
Remove skin of one peach and slice thinly; set aside.
Place pretzels in a small ziplock bag and crush lightly with a rolling pin/pan.
Whip the cream until soft peaks form. Reserve about 1 cup and refrigerate for serving later.
Place 8 crackers in the bottom of the lined baking dish.
Add about 1 cup of cream into the softened jam and mix with a rubber spatula until combined. Fold in remainder of cream and blend until fully combined.
Spread a layer of cream over crackers. Add another layer of crackers and repeat with cream, then one layer of sliced peach. Keep layering crackers/ cream until you reach the top of the baking dish. Finish with a layer of cream. Cover with plastic wrap and refrigerate at least 5 hours.
When ready to serve, invert the dessert onto a serving platter and remove/discard plastic wrap. Place in the freezer for 20-30 minutes, to make it easier to slice.
Remove from freezer. Using remaining/chilled whipped cream, spread a thin layer all over dessert to cover edges for a finished look.
Slice the remaining peach (skin on) and place on top of dessert. Sprinkle with pecans and pretzels; serve in slices.