Ease of finding the necessary ingredients = 4 out of 5

Veal does not seem to be a meat that is available at your local grocer but it may be possible to locate at a more specialised meat store. I have no particular craving for this type of meat so did not go to the trouble of searching for it with any kind of effort.

You have the option of going with Gruyere as it can be located in slab form by Happy Cow. Gouda can also be bought in a cheese ball version done be Kotmale. But, as the easiest-option kind of cook, there was hardly a hesitation when going with the pre-shredded product provided.

You will find the diced tomatoes next to the canned fruit section rather than with the tomato puree or sauces.

DIRECTIONS

Preparation Time = 45 minutes (due to the required amount of slicing and dicing involved)

Cooking Time = 1 hour (keep in mind that there are 2 separate dishes to cook and an assembly involved)

Baking time = 40 minutes.

Prepare Meat Sauce :

In a microwave-safe 1-cup liquid measuring cup, heat 1/2 cup water in microwave oven on High for 1 minute. Stir in porcini mushrooms; let stand 15 minutes.
I am leaving the instructions pertaining to this particular variety of mushrooms just in case someone else has knowledge about where to obtain them from in Sri Lanka.

Meanwhile, in a 12-inch skillet, heat the oil over medium heat until hot. Add the garlic, carrots, and onion. Cook for 15 minutes or until vegetables are tender, stirring occasionally. Increase heat to high before adding the beef, pork, and veal, and cook for another 10 minutes or until meat is browned, breaking it up with the side of the spoon.

While meat is browning, with a slotted spoon, remove the porcini mushrooms from soaking, reserving the liquid remaining. Rinse mushrooms to remove any grit then coarsely chop. Strain the liquid through a sieve lined with a paper towel.

Add wine to the meat in the skillet and heat to boiling for 2 to 3 minutes or until most of the liquid evaporates.

Stir in tomatoes with their juice, salt, and the mushrooms along with the reserved soaking liquid. Heat to boiling then reduce to medium-low to simmer, uncovered, for 20 minutes or until sauce thickens slightly, stirring occasionally.

Preheat oven to 375° F (190° C).

Prepare Béchamel Sauce :
In a 2-quart saucepan, melt the margarine over medium heat.

With a wire whisk, stir in the flour, pepper, salt, and nutmeg and cook for 1 minute.

Gradually add the milk and heat to boiling, stirring frequently with the whisk to prevent lumping.

Remove saucepan from heat and set aside.

In a small bowl, stir in the Fontina and Parmesan until well combined.

Assemble lasagna:

Spoon 1 cup of the Meat Sauce, evenly, in to the bottom of a 13" by 9" glass baking dish.
My recommendation would be to top this meat layer with one of Béchamel sauce and cheese filling before going on to the pasta. If not you may find that the creamy taste is isolated to only the top of the dish.

Arrange 4 noodles over sauce, overlapping slightly and making sure they do not touch sides of dish. (If your package of lasagna noodles has only 12 noodles, use 3 noodles per layer and do not overlap them.)
It is important to keep in mind that the lasagne slates shrink as they cook and recover moisture in to their make-up. Thus, in order to keep the integrity of your lasagne intact, make sure that there are no gaps between the sheets (I would say that you could safely overlap them to up to 1cm)

Spoon about 1 and a 1/2 cups of the Meat Sauce over the noodles. Spread about 2/3 cup Béchamel Sauce over the meat; then sprinkle with about a 1/2 cup of the Cheese Filling.

Repeat this layering 3 more times, beginning with the remaining noodles, then the meat sauce, followed by the béchamel sauce, and ending with the cheese filling.

Cover lasagna with foil, preferably nonstick, and bake for 30 minutes. Remove foil and bake for 20 minutes longer or until heated it is through and the cheese is lightly browned. Let it stand for 10 minutes for easier serving.
Unfortunately any for m of foil is unavailable in this country, so just baked for 40 minutes without it.

Sadly, I have to say that this did not come out as well as I had hoped. While they recommend for about 4 layers, I only managed about 3 due to the size of the dish which I used. The meat sauce ended up tasting a little bland, leading me to suggest a substitution of 5 tablespoons of tomato puree for the can of diced tomatoes in order to make it richer and more flavoursome. I would also double the amount of béchamel sauce prepared next time around so I have enough for all the required layers. I may also use the mozzarella variety of cheese instead of the Gouda just because I prefer the taste.

In essence this is a recipe of sophisticated taste which just needs a few tweaks here and there to make it perfect. So, chalking this round up as a useful error which informed well for the next trial.