Grease an 8x8 pan with cooking spray, then line the pan with aluminum foil allowing foil to hang over the edges and grease again.

In the bowl of a stand mixer, beat the 2 sticks of butter, sugar and salt on medium speed until soft and light, about 2-3 minutes. Beat in the vanilla.

With the mixer on low, add 2 & ¼ cups of the flour, beating just until the dough is smooth and the flour has been absorbed, stopping to scrape the sides of the bowl as necessary.

Transfer ½ of the dough into the prepared baking pan. Press the dough evenly into the pan to form the bottom layer. Put the pan in the refrigerator while you make the filling and top layer.

Add the remaining ¼ cup of flour to the remaining dough in the mixer bowl and work it in with your hands until crumbs form. Set aside.

In a medium saucepan, combine the butter, honey, brown sugar, condensed milk, and vanilla. Bring to a simmer, whisking occasionally. When the mixture begins to boil, add in the diced apples and whisk frequently until it begins to thicken and darkens in color slightly, about 10 minutes. Remove from the heat and let cool while you preheat your oven.

Preheat the oven to 350 degrees. Remove the pan from the refrigerator and pour the caramel apple filling over the bottom crust. Use the back of a spoon to spread it evenly. Sprinkle the crumb topping over the filling.

Bake for about 1 hour, or until the filling is gently bubbling and a dark caramel color. If your edges start to get too dark, cover with foil while you continue baking. Cool the bars in the pan about 15-20 minutes. Use the foil to lift the bars out of the pan and onto a cutting board.

Once completely cool, cut into bars.