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Stawberry Rhubarb Custard Square

This is an old traditional family recipe from Grandma Maude that I loved but haven't made for years because I forgot about it. Cleaning out the recipe bin brought me face to face with some poignant Alberta prairie family memories. Makes 1 9-inch by 13-inch square, or two long bottom removable tart shells: serves 8-12

Course Dessert
Cuisine Canadian
Prep Time 20 minutes
Cook Time 25 minutes
Total Time 45 minutes
Servings 12
Author Valerie Lugonja


Ingredients for the Crust:

  • 1 cup or 170g cold butter , cubed
  • 1 1/2 cup or 350g flour
  • 1/2 cup or 100g sugar

Ingredients for the Custard:

  • 2 eggs
  • 1 cup or 210g white sugar
  • 1/2 cup or 100g brown sugar
  • 1 cup or 150g flour
  • 1 teaspoon or 5g baking powder
  • 1 teaspoon or 5g salt
  • 1 pound or 500g fresh rhubarb , preferably red, sliced into pieces about a quarter-inch wide


  1. Preheat the oven to 350F

Instructions for the Crust:

  1. Cut the butter into the flour and sugar as you would for pie pastry
  2. Press dough into a 9" by 13" pan

Instructions for the Custard:

  1. Beat eggs in large bowl until foamy; add sugars
  2. Cream slightly; add flour, baking powder, and salt
  3. Fold to combine; add rhubarb
  4. Gently mix together; allow mixture to sit for about an hour

Putting it all together:

  1. Pour the custard over the crust and smooth it evenly
  2. Bake at 350°F for 25-30 minutes: until set and a nice golden crusty colour
  3. Preheat the oven to 350F

Thermomix instructions for the crust:

  1. Scale butter, flour and sugar into the TM bowl; set time at 30 seconds and speed at 2-3
  2. Press dough into a 9" by 13" pan or two narrower tart pans, like I did

Thermomix instructions for the custard:

  1. Scale both sugars into the TM bowl; add eggs
  2. Place butterfly securely in place and remember to never use it over speed 4; set time at 1 minute and speed at 4
  3. Scrape down sides of the bowl with a rubber spatula; scale flour, baking powder, and salt into TM bowl
  4. Set time to 20 seconds on soft speed, watching through hole in the lid, go to 0.5 speed and then to speed 1; combine for 10 more seconds if not thoroughly combined
  5. Scale thinly sliced red tart rhubarb into the TM bowl; still with the whisk, set the speed to soft and the time to 15 seconds
  6. Watching through the hole in the lid, gently stir from speed soft to 0.5 for 15 seconds until fully combined
  7. Pour mixture onto pastry crust; set aside for 30 minutes to macerate

Putting it all together:

  1. Bake at 350°F for 25-30 minutes: until set and nice crusty golden brown colour