Preheat the oven to 350℉ and line a 9x13 inch pan with parchment paper.
In a large bowl or the bowl of a stand mixer, combine the butter, sugar, vanilla and salt.
1 1/2 cups salted butter*, 1 1/4 cups sugar, 2 teaspoons vanilla extract, 1/4 teaspoon salt*
Add the flour and stir until combined.
3 cups flour
Press about 2/3 of the mixture into the prepared pan; cover and refrigerate the remaining dough until ready to use.
Bake for 15 minutes.
Combine the diced peaches, sugar, cornstarch and cinnamon.
3 cups peeled and diced peaches, 1/4 cup sugar, 2 teaspoons cornstarch, 1/2 teaspoon cinnamon
Spoon the peach mixture over the crust and spread to an even layer.
Top with remaining crumb mixture.
Bake an additional 30-35 minutes or until golden brown and bubbly.
Let cool before cutting into squares.