📖 Instructions

1. Preheat your oven to 350°F (175°C). Get your oven ready, it needs to be hot when the crust is ready to bake.
2. Make the shortbread crust: In a large bowl, whisk together the flour, powdered sugar, and salt. This ensures everything is evenly distributed for a consistent crust. Don't skip the salt, it balances the sweetness.
3. Cut in the butter: Add the cold, cubed butter to the flour mixture. Use a pastry blender or your fingertips to cut the butter into the flour until the mixture resembles coarse crumbs. The colder the butter, the flakier the crust. I sometimes chill my bowl and the butter beforehand.
4. Press into the pan: Press the mixture evenly into the bottom of an ungreased 9x13 inch baking pan. Use the bottom of a measuring cup to firmly pack it down. A well-packed crust will hold its shape better.
5. Bake the crust: Bake for 18-20 minutes, or until the crust is lightly golden. Watch it carefully, as ovens vary. You want it to be set but not overly browned. Let the crust cool slightly while you prepare the filling.
6. Prepare the rhubarb: While the crust is baking, wash and chop the rhubarb into 1/2-inch pieces. Set aside. Fresh rhubarb is best, but frozen (thawed and drained) can work in a pinch.
7. Make the custard filling: In a large bowl, whisk together the eggs, granulated sugar, flour, salt, and vanilla extract until smooth. Make sure there are no lumps for a silky smooth custard.
8. Add the sour cream and milk: Whisk in the sour cream and milk until well combined. The sour cream adds a lovely tang that complements the rhubarb.
9. Combine rhubarb and filling: Gently fold the chopped rhubarb into the custard mixture. Be gentle so you don't crush the rhubarb.
10. Pour over crust: Pour the rhubarb custard filling over the slightly cooled shortbread crust. Distribute the rhubarb evenly for consistent flavor in every bite.
11. Bake the bars: Bake for 35-40 minutes, or until the custard is set and lightly golden. The center should be set but with a slight jiggle. If the crust starts to brown too quickly, tent it with foil.
12. Cool completely: Let the bars cool completely in the pan on a wire rack. This is crucial for the custard to set properly. Resist the urge to cut into them while they're warm!
13. Chill (optional): For even cleaner cuts and a firmer texture, chill the bars in the refrigerator for at least an hour before serving. But honestly, sometimes i just can't wait!
14. Dust with powdered sugar: Before serving, dust the bars with powdered sugar for a beautiful presentation. It also adds a touch of extra sweetness.
15. Cut and serve: Cut the bars into squares and serve. Enjoy every tart, sweet, creamy bite!