Make lasagna sheets and set aside

Preheat the oven to 375?F

Wrap each unpeeled garlic head in aluminum foil, set in the oven, and roast for 20 minutes

Cool in the foil until easy to handle, then pull off the garlic cloves one by one and pinch, squeezing the flesh into a small bowl, mash the garlic and set aside

Cook the lasagna noodles al dente, rinse with cold water, drain and set aside to cool

Meanwhile, heat the olive oil in a heavy 10- inch skillet over moderate heat for 1 minute

Add the onion and zucchini and cook, uncovered, until soft, about 5 minutes

Add the mushrooms and cook, uncovered, 3 minutes longer

Add the peas and cook 3 more minutes

Stir in the lemon juice, pepper, and pimiento and remove from the heat

In a small saucepan, whisk the milk into the flour; set over moderately low heat and cook, stirring, for 4 minutes or until thickened

Mix in the oregano, cheese, and reserved garlic

Measure out 1/2 cup of the sauce and reserve

Combine the rest with the zucchini mixture

To assemble the lasagna, line the bottom of an ungreased 8"x 8"x 2" baking pan with the cooked lasagna noodles, cutting them to fit and reserving the scraps

Spread half the zucchini mixture over the noodles, add a second layer of noodles, spread with the remaining zucchini mixture, then top with the noodle scraps

Finally, smooth the reserved sauce evenly over all

Cover with aluminum foil and bake 20 minutes; uncover and bake 15 more minutes.