Preheat oven to 350 °F. For crust: Mix pretzels, melted butter and sugar together with your hands until well mixed. Then press evenly into a non-greased 9x13 glass pan. Bake for 4 minutes at 350 °F. When done let cool for approximately 30 minutes. For the filling: While crust is cooling, beat with electric mixer the cream cheese, extra creamy whipped cream, pureed mango and sugar until well blended and smooth. Then spread evenly over top of pretzel crust. Lastly take a butter knife and run along edges to seal. For Mango Topping: Combine lemon gelatin with boiling water in medium size bowl. Next, whisk in mango jam, pureed mango and sugar until gelatin and sugar are dissolved. Now, put diced mango in food processor and pulse 4-6 times. Once chopped, stir into gelatin mixture and stir well. Then pour over cream cheese layer and chill in refrigerator 3 to 4 hours. Note: for fast setting put in freezer for 30 minutes then into the refrigerator until set.