Preheat your oven to 180 degrees Celsius or 350 Fahrenheit.
Grate your pumpkin coarsely. Cut the chicken breasts into very small pieces.
Heat a large pan over moderate heat and add the curry paste. Stir well for 1 minute than pour in the coconut milk. Fill the empty can with water and add that to the pan as well. Bring everything to a boil, add the lemon juice and the soy sauce and let simmer for about 3 minutes. Put the chicken and the pumpkin in the pan, bring to a boil, reduce heat and cook, covered, until everything is soft. The sauce should still be quite runny, if it is not, add a bit more water.
Layer everything in a rectangular, oven proof form, starting and ending with the sauce. You should have 4 layers of sauce and 3 layers of lasagne sheets.
Mix the cheese and the breadcrumbs together and sprinkle them over the last sauce layer. Put the lasagne in the hot oven and bake it for 30 minutes or until the lasagne sheets are cooked through and the cheese is golden brown. Turn off the oven and let sit inside for another 10 minutes.