Preheat the oven to 175°C (fan).

Rinse and chop the mushrooms into small pieces along with the onion and garlic. Sauté it all in a pan with a bit of oil. Add the spices: rosemary, paprika, and cumin. Sprinkle generously with salt and pepper, and fry for a couple of minutes until the mushrooms are golden and soft. Let cool on a plate.  

Roughly chop the walnuts and toast them in the pan over low/medium heat until they are golden. Let them cool on a plate. 

Drain the tofu and place a piece of kitchen paper or a tea towel over and under the tofu. Press down to squeeze out the water. Do this a few times all over so the tofu is as dry as possible. The more water you squeeze out, the better the result. Crumble the tofu into tiny pieces in a bowl. 

In a food processor or mini chopper, finely chop the walnuts. You can also chop them finely with a knife. Add finely chopped tofu, the sautéed mushrooms, soy sauce, tomato purée, and a bit of lemon juice to the mini chopper. Blend everything well at low/medium speed until you have a firm and finely chopped consistency.  Now add flour to the mixture and gently stir with a spoon. Place the mixture on a baking sheet lined with parchment paper. Shape the mixture with your hands so it measures approx. 20 cm long and 12 cm wide. Bake in the oven for 30 minutes. Let the mixture cool for 10 minutes afterward. 

Roll out the puff pastry into an elongated rectangle on the baking sheet and place the baked mixture in the center of the puff pastry. Cut lines on the sides of the puff pastry (see attached picture) and alternately place a piece of puff pastry over the mixture. Brush with a bit of oil between the pieces so the puff pastry sticks well.

Bake the loaf for 25-30 minutes until golden on top.