Pile flour on the work surface, make a well in the center and place an egg and a little water to the well. Cut butter into small pieces and arrange around the well. Quickly knead into smooth pastry. Shape into a ball and wrap in foil, refrigerate for 1 hour.
Cut bacon into small cubes and cook in a hot pan for a few minutes, set aside. Peel onions and cut into rings. Heat butter in a pan and saute onions until soft. Whisk eggs with cream fraiche, cumin powder, 2/3 of bacon and onions, season with salt and pepper.
Roll out pastry on a floured surface and arrange in a lined with parchment paper baking pan, making about 3 cm (approximately 1 inch) edge all around. Prick bottom with a fork several times and spread egg and onion mixture on top. Sprinkle with remaining bacon and raisins and bake in preheated oven at 200°C (approximately 400°F) for about 30 minutes. Remove from the oven and serve.