• Cook the frozen spinach in boiling water for 10 minutes until soft. Squeeze out all excess water, we want it very dry.
• Heat up olive oil in a pan. Add onion, celery and carrot with a pinch of salt and cook for 5 minutes. Add tomato paste and mustard, mix to combine then add mushrooms. Cook for 5 minutes or until all the water released has evaporated. We don't want it to be watery. Mash the mixture roughly with a hand blender.
• Preheat oven to 190C/375F
• In the meantime, add walnuts to a blender and blend them until ground. Do the same with flax or chia seeds.
• In a big bowl, add the lentils and mash them roughly, then add ground walnuts, spices, ground flax or chia seeds, soy sauce and the mushroom mixture and mix to combine. Add breadcrumbs and mix again. With cling film or baking paper, shape the mixture into a loaf.
• Take the puff pastry and make it longer by flattening slighlty with a rolling pin. Now spread cooked spinach and sun dried tomatoes in the middle and add the lentil loaf.
• Fold the sides over it and make sure it’s sealed. (In the picture you can see strips, but i find that's less practical even though it looks prettier) Then make some oblique cuts with a knife. Brush with some plant milk and cook at 190C/375F for 30-40 minutes or until golden brown.

Gravy

• Combine all the ingredients except the vegetable broth for the gravy in a pot, adding the vegetable broth slowly while mixing not to create lumps. Cook on medium/low heat for about 5 minutes, stirring often, stir until it reaches your desired consistency.