Mom s Rhubarb Custard Torte

2 cups all-purpose flour

2 cups quick cooking oats

¾ cup packed brown sugar

¾ cup vegetable shortening

½ teaspoon salt

8 cups sliced fresh rhubarb

12 eggs

1 cup white sugar

½ cup all-purpose flour

1 pinch salt

½ teaspoon ground cinnamon, or to taste

2 tablespoons butter, cut into small chunks - or as needed

Preheat oven to 350 degrees F (175 degrees C).

Mix 2 cups flour, oats, brown sugar, vegetable shortening, and 1/2 teaspoon salt in a large mixing bowl until the ingredients are crumbly. Reserve 3/4 cup of the crust mixture in a bowl and press remaining crust mixture into the bottom of a 9x13-inch baking pan.

Spread rhubarb evenly over the crust. Whisk eggs, white sugar, 1/2 cup flour, and 1 pinch of salt in a bowl until smooth; pour the egg mixture over the rhubarb. Scatter the reserved oat mixture over the top. Dust the torte lightly with cinnamon and spread small butter chunks evenly over the top.

Bake in the preheated oven until a knife inserted into the center of the torte comes out clean, about 1 hour. Refrigerate at least 6 hours or overnight before serving.