Preheat the oven to 375 degrees. Bring a pot of water to boil for the pasta, and salt it. Use cooking spray to grease one 9-by-13-inch baking dish.

Cook the jumbo pasta shells in the boiling water until just under al dente. Drizzle a large baking sheet lightly with oil, and spread the shells out on it to allow them to become cool enough to handle.

In a sauté pan, heat the olive oil and 1/2 tablespoon of butter, and add the shallot, garlic, zucchini, broccoli, and spinach. Season, and cook until fragrant and soft, about 5 to 7 minutes. Set aside to cool.

Meanwhile, mix the ricotta, 4 ounces of chèvre, the egg yolk, the mint and tarragon, and the peas in a large bowl. When the vegetable mixture has slightly cooled, add it to the cheese mixture, and mix to combine.

Make the bechamel by adding the olive oil to the warm pot. Whisk in the flour, and allow to cook over medium heat—watching with a close eye for about 3 or 4 minutes, until the mixture thickens but does not overly brown. Whisk in the milk and cook until slightly thickened only enough to coat the back of a spoon. This won’t thicken as much as a traditional bechamel, so just whisk as you heat it through. Season with salt, pepper, and a pinch of nutmeg.

Stuff the shells with the cheese mixture — I use a pastry bag or a ziploc bag with a corner cut off — and place seam-side-down in the baking dish. Pour the bechamel over and top with Parmesan.

Total baking time will be 60 minutes. First, bake the shells covered for 30 minutes at 375. Then raise the heat to 400, and bake another 30 minutes uncovered, or just until the top is golden and bubbly.