Preheat oven to 400° and spray a 13 x 9" baking dish.
Crush pretzels in a sealed bag (use a meat mallet or rolling pin) and mix with brown sugar.
Stir in melted butter and press mixture into the baking dish. Bake for 10 minutes, then cool completely on a wire rack.
Beat cream cheese with sugar until smooth, then fold in whipped topping. Spread evenly over cooled crust.
In a large bowl, dissolve gelatin in boiling water, then stir in sliced strawberries. Refrigerate until slightly set.
Pour gelatin mixture over cream cheese layer, spreading strawberries evenly. Refrigerate for 4 hours or overnight.
Optional: Garnish with whipped topping, extra strawberries, and/or pretzels.