Onion Tart with Rye Crust Recipe

In small saucepan or microwave-proof bowl, warm ¾ cup (175 mL) of the milk to 100F (38C). Pour into bowl; sprinkle with ½ tsp (2 mL) of the yeast. When yeast starts to foam, stir in 1 cup (250 mL) flour; mix vigorously with 100 strokes. Cover starter with plastic wrap; let sit at room temperature overnight.

Stir remaining ½ cup (125 mL) milk and 1 tsp (5 mL) yeast, and salt into starter. Gradually mix in remaining flour, adding up to ½ cup (125 mL) more flour as needed, until dough forms ball. Transfer to floured work surface and knead until smooth but still sticky, about 10 minutes. Place in greased bowl; cover with plastic wrap. Let rise in warm place until doubled in volume, about 2 hours.

Punch down dough. On floured work surface, roll out dough to fit 12- x 17-inch (30 x 43 cm) lightly greased rimmed baking sheet or 12-inch (30 cm) pizza pan, folding edges over and pinching down to form small crust. Cover with kitchen towel; let rise for 45 minutes in warm place.

Filling: Meanwhile, in large skillet over medium heat, fry onions in oil, stirring often, until golden, about 30 minutes.

Spread sour cream over dough; scatter prosciutto and caraway seeds over top. Cover evenly with onions and sprinkle with salt and pepper. Bake in bottom third of 375F (190C) oven until crust is crispy and topping is nicely browned, 55 to 60 minutes.