Preheat oven to 350°F. Line a 9x13” pan with foil and spray with nonstick cooking spray.
Cream butter and sugar with a stand mixer fitted with the paddle attachment (or you may use a hand mixer). Once the mixture is creamed and fluffy, mix in the eggs and vanilla extract until smooth, then mix in the baking soda, cream of tartar, and salt. Slowly mix in 4 cups flour until the mixture is just combined, then stir in the chocolate chips.
Press about 2/3 of this mixture in the bottom and about 1/2” up the sides of the prepared pan.
Stir the caramel sauce and remaining 1/4 cup flour in a small bowl. Pour over the top of the dough. Drop spoonfuls of the remaining dough evenly over the top of the caramel.
Bake for 25-33 minutes, or until the top looks done and is golden around the edges. It will still be someone jiggly in the center. Cool completely before cutting. It’s easier to cut when it’s chilled.
Store in an airtight container for up to 3 days or freeze for up to 1 month.