In a separate bowl, beat custard ingredients together (I used a mixer for this) and pour over rhubarb.
Bake 10 minutes at 400°, and then 45-60 minutes at 350° until the center is just slightly jiggly (see note). The custard temperature should be about 175 F if you have an instant read thermometer. If the crust is getting too brown, you can shield with foil.
Cool briefly on the countertop, then move uncovered to the refrigerator to get thoroughly cool and set before serving. Store leftovers refrigerated and lightly covered.
Notes
The biggest complaint in online reviews of this recipe is failure to set. The custard will have a slight jiggle when done, but if it wobbles more than than, cooke it longer, covering crust with foil if needed.
Nutrition
Calories: 247kcal
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.