• Preheat the oven to 300°F (149°C). Spray the sides and bottom of an 8x8 inch square baking pan with cooking spray, then set aside. Alternatively, you can line the baking pan with parchment paper but I always get too frustrated with trying to push down the corners so I scrapped that here.

Make the shortbread:

• In a stand mixer fitted with paddle attachment, cream softened butter with vanilla and confectioner’s sugar on low speed until combined. Gradually add the flour, oat flour, cornstarch, and salt, mixing until you have a nice looking dough -- about 3 minutes depending on your mixer. Press the mixture into your square baking pan and bake for 15 minutes. While that is baking, prepare apples and streusel. Remove from oven and set aside.

Make the apple pie filling:

• Mix the sliced apples, flour, brown sugar, cinnamon, ginger, cloves, and nutmeg together in a large bowl until all of the apples are evenly coated. Set aside. You’re going to wait for the apples to release some of their moisture and strain that off so the bars don’t get soggy.

Make the streusel:

• Stir the melted butter, oats, brown sugar, cinnamon, and flour together in a medium bowl. Mix until the mixture resembles coarse crumbs, using your hands towards the end to really mix it all together. Set aside.
• Turn the oven up to 350°F to preheat. Arrange apple mixture on top of shortbread crust, pressing them down to fit. If you think you have too many, don’t feel like you need to use them all! You can save some for making oatmeal or mini turnovers or something fun.
• Sprinkle the apple layer with streusel, pressing down lightly to make sure they’re all touching the apples. Bake for 30 minutes, checking to make sure streusel is golden.
• Remove from oven, cool for 20 minutes, then chill in fridge for a few hours. This will make it easier to cut into bars when you serve them.

Make the salted caramel sauce:

• While the bars are chilling, it’s caramel time.
• Place water in a medium saucepan, then ppur the sugar into the center of the pan, making sure it doesn’t touch the sides. Cover, bring to a boil over high, and once boiling, uncover the pan and continue boiling until syrup registers 300 degrees on a digital thermometer. This takes around 7-8 minutes.
• Reduce heat to medium, and continue to cook until syrup is deep amber and registers at 350 degrees, roughly 1-2 minutes. Watch your caramel LIKE A HAWK during this time.
• While waiting for 1-2 minutes, bring the cream and salt to a simmer in a small saucepan on high heat.
• Remove the pan with the sugar syrup from heat and very carefully pour ½ of the hot cream into it. It will bubble vigorously, so be careful! Let bubbling subside, then add remaining cream, vanilla, and lemon juice, whisking cocntinuously until caramel is smooth.
• Cool and refrigerate, as caramel will thicken up a bit as it cools. You’ll have leftovers, so save those bad boys in an airtight container for up to two weeks!
• Cut into 16 or 12 bars. Drizzle salted caramel sauce on top of each bar when serving.