Preheat oven to 350°. In a 9x13 dish, make a foil sling. Lay down one longer piece first, then a slightly shorter piece on top of that making sure the foil goes up the sides all the way around. Press into the dish. Spray with nonstick spray.
For the crust: Combine flour, sugar and salt in a bowl. Add melted butter and stir with a rubber spatula until evenly moistened. Crumble dough over bottom of prepared pan. Using bottom of a dry measuring cup, press down to make an even layer. Poke the crust with a fork several times all over, about 20 times. Bake for 20 minutes until edges are browning. Remove from oven and let cool completely, about 30 minutes.
For the filling: combine cream cheese and butter in the bowl of a stand mixer. On low speed, slowly add the sugar and mix until combined, about a minute. Scraping down sides as needed. Increase speed to medium-high and mix until light and fluffy, about 2 minutes.
Reduce speed to low, add the eggs one at a time and mix until incorporated. Add vanilla and salt and mix, scraping down sides as needed. Increase speed to medium-high and mix until light and fluffy. Mixture should have consistency of frosting. Spread filling on top of cooled crust. Tap pan gently to remove any air bubbles.
Bake 30-35 minutes or until top is golden brown, edges have cracked and center is slightly jiggly when pan is shaken.
Let cool completely, at least 3 hours. Using foil overhang, lift bars out of the dish, dust with powdered sugar and cut into bars. Leftovers can be kept in an airtight container at room temp for up to 3 days or in the refrigerator for up to 5.