Preheat the oven to 180ºC.
Heat the oil in a large pot. Add the onion and garlic and sauté fortwo minutes. Stir in the carrot and thyme.
Add the mince and brown. Season with salt and pepper and use a fork to break up any lumps. Add the tomatoes, passata, tomato sauce and garlic and herb seasoning. Stir, then cover and leave to simmer for 30 minutes over a low heat.
To prepare the sauce, melt the butter in a large saucepan over a medium heat. Add the flour and stir on the heat for 2 minutes. Remove from the heat and gradually add the milk while whisking.
Return the pot to the heat and stir continuously until the sauce thickens and starts to boil. Season to taste, remove from the heat and stir in the cheese.
To assemble, spoon a few tablespoons of the meat sauce onto the bottom of the lasagne dish. Arrange a layer of pasta sheets on top, and top with another layer of meat. Sprinkle all the cheese over the top and drizzle with pesto. Pour half of the cheese sauce on top, followed by the remaining pasta sheets and meat sauce. Finish with the remaining cheese sauce.
Let the lasagne stand for 10 minutes before baking. Cover the dish with a lid or foil and bake for 40 minutes. Remove the lid, sprinkle paprika over the sauce and top with tomatoes. Bake for a further 10 minutes.