Preheat the oven to 450°; spray a 13 x 9 inch baking dish with cooking spray.
Saute the onions in a skillet over medium-high heat with olive oil until just soft.
Stir in the garlic, and cook another minute until just aromatic.
Add the tomatoes, rosemary, oregano, and basil.
Continue to cook until all moisture has evaporated, about 10 minutes.
*Toasting the bread crumbs--in a nonstick skillet, melt 1 tablespoon butter; add the bread crumbs and combine, stirring to coat evenly while cooking; cook until golden brown and aromatic, about 5 minutes; remove from heat and let cool.
To assemble--Layer 1/2 of the lasagna noodles in the prepared casserole dish; top with half of the sliced potatoes, and season with salt and pepper.
Top the potatoes with half of the tomato mixture, and sprinkle with half the cheeses.
Repeat layering, ending with cheese; sprinkle evenly with toasted bread crumbs.
Cover the gratin with foil and bake for 30 minutes; remove the foil and bake 15-20 minutes to brown the cheese.
Let stand 5 minutes to set the cheese before slicing and serving.
Cut in smaller portions and serve as a side dish with roasted chicken; or cut in larger portions to serve as a main meal.