- 250 grams Broccoli
- 2 Red onions (about 40 grams)
- 750 grams white Asparagus
- 300 milliliters Vegetable broth
- 80 grams Rye groat
- 120 grams Pastry flour ((type 550º)
- ½ teaspoon Cream of tartar
- 80 grams Cultured butter (cold)
- 1 tablespoon Fat (for the form; 10 grams)
- 2 Eggs
- 100 grams Sour cream (24% fat)
Rinse, trim and cut broccoli into small florets. Peel onions and cut into thin rings.
Rinse asparagus, peel, cut off woody ends and cut into 5 cm (approximately 2-inch) long pieces.
In a large pot, bring vegetable broth to a boil. Add asparagus, cover and cook over medium heat until tender, about 5 minutes. Remove asparagus with a slotted spoon, place on a large plate and let cool.
Add onions to the broth, return to a boil and cook for 2 minutes. Add broccoli florets and cook for 1 minute.
Strain vegetable broth through a sieve. Place the vegetables on a large plate and let cool.
Meanwhile, mix rye flour, pastry flour, cream of tartar and 1/2 teaspoon salt in a mixing bowl. Cut butter into small pieces. Add 5 tablespoons cold water and the cold butter to the flour mixture. With a hand mixer fitted with a dough hook attachment, mix dough until smooth.
Roll about 2/3 of the dough on a floured surface into a 30 cm (approximately 12-inch) disc. Wrap the remaining 1/3 of the dough in plastic wrap and refrigerate.
Press the rolled dough into the bottom of a 28 cm (approximately 11-inch) diameter tart pan and pierce several times with a fork. Bake in preheated oven at 200°C (fan oven 180 ° C, gas mark 3) (approximately 400°F/convection 350°F) on the middle rack until golden brown, about 10-15 minutes. Remove from oven and let cool slightly.
Meanwhile, mix eggs, sour cream and 100 ml (approximately 1/4 cup) of cooled vegetable broth in a large bowl until smooth. Season to taste with salt and pepper.
Remove remaining dough from the refrigerator and roll into 2 thin (about 42 cm) (approximately 16-inch) long roll shapes. Press rolls into the inside rim of the tart pan to form an edge.
Fill tart with asparagus, broccoli and onions. Pour in the egg-sour cream mixture. Bake in a preheated oven at 200°C (fan oven 180°C, gas mark 3) (400°F/convection 350°F) on the middle rack for 30 minutes. Season to taste with coarsely ground pepper and serve.