In an oiled skillet, brown the finely chopped onion and garlic for 3 minutes.
Add the seafood, season with salt, pepper and cumin, and cook for 7 minutes.
In a saucepan, put the butter and flour over low heat, knead with a wooden spoon and add the milk little by little. Increase the heat gradually while stirring until thickening of the sauce. Add 50 grams of grated cheese, season and remove from heat.
In a baking dish, lay a layer of Randa lasagna sheets, pour in the white sauce, add the seafood, sprinkle 30 grams of grated cheese and cover with a layer of Randa lasagna sheets. Repeat until the end.
Finish with a layer of Randa lasagna sheets and white sauce, and top with the remaining grated cheese.
Put in the oven at medium temperature for 30 minutes. Serve hot