Easy Rhubarb Custard Bars Recipe

To begin, gather the ingredients for these rhubarb custard bars. You'll need a package of sugar cookie mix — Betty Crocker makes one perfect for this purpose. Instead of preparing a cookie base from scratch, a pre-made mix incorporates what you need to make melt-in-your-mouth dough. Simply add some softened butter to facilitate blending and one egg to bind everything together. If you want to make your own dough, Morone says it's fine "as long as it is baked to light golden brown before the filling is added." 

Next, for the custard filling, you'll need to round up a few more eggs, granulated white sugar, heavy cream (or coconut cream for a tropical twist), flour, and vanilla extract. Vanilla adds plenty of warm aromas while enhancing those of the other ingredients. If you want to substitute the white sugar, Jessica suggests, "[You can use] Splenda or coconut sugar in a 1:1 ratio, or use one cup of honey or maple syrup." To add a bit of zing and color, chop up some fresh rhubarb, and add it to the custard mixture. If you're not used to cooking with rhubarb, choose firm glossy stalks, and cut them into small pieces so that they cook evenly. It is sour if eaten alone, but a great match to balance the sweetness of baked goods. If you'd rather choose something more familiar, Morone remarks, "I bet it would work really well with strawberries or a strawberry rhubarb combination."

Once the cookie mixture is thoroughly combined, pour the mix into your prepared baking dish. Using a spatula or your hands, press the dough so that it covers the entire dish. You'll need to make sure the dough is pressed against the sides, or else your custard mixture will spill over. By preparing a smooth cookie base from one end of the dish to the other, your bars will have a distinct cookie layer, topped with custard. 

Bake the cookie dough base in the preheated oven for 10 to 15 minutes, until the crust is a light golden brown. It will return to the oven once the custard goes on top, so be careful not to overcook it. When the crust is sufficiently golden, remove it from the oven, and reduce the temperature to 350 F. 

Carefully pour the custard rhubarb mixture over your pre-baked cookie crust. You can spread the rhubarb around with a spatula if the distribution is a bit uneven. This will ensure each bite has the right blend of creamy and tart. At this point, your oven should be at the right temperature, so you can pop your baking dish back in, and set the timer for 40 to 45 minutes. As you approach the 40-minute mark, check the custard for doneness. The custard should not ripple when you give the pan a shake. Instead, Morone says, "The custard filling is set when it jiggles slightly when you gently nudge the pan."

When you're ready to taste these heavenly rhubarb custard bars, remove them from the refrigerator. For a decadent pairing, Morone loves adding a dollop of whipped topping to the bars. The creamy texture from the custard and the whip melts in your mouth along with the sugar cookie base. The sour rhubarb, now softer and subtler after its time in the oven, is a tasty contrast. If you've never baked with rhubarb before, after trying these, you'll realize it's the touch of tartness you've been missing all along.

According to Morone, these bars will keep up to five days in the fridge, although we doubt they'll last that long! Custard is not a great candidate for the freezer, because it tends to split, compromising the creamy texture. You're better off making a fresh batch for the occasion.