Spring Vegetable Lasagna with Fresh Spinach Pasta

To prepare pasta: Heat oil in a medium skillet over medium heat. Add 3 cups spinach and cook, stirring, until wilted, about 1 minute. Transfer to a cutting board and finely chop.

Combine flour and 1/2 teaspoon salt in a large bowl. Make a well in the center and add egg yolks, water and the spinach. Knead the dough until it comes together then turn out onto a lightly floured work surface. Knead the dough until smooth and elastic, about 7 minutes. Form into a ball, wrap in plastic and let rest at room temperature for 1 hour.

Flatten the dough slightly on a lightly floured surface and cut into quarters. Rewrap three of the quarters separately. Working with one quarter at a time, flatten the dough into a rectangle. With the sheet roller of a pasta machine on the thickest setting, roll the dough, short-edge first. Fold the dough in thirds like an envelope, lightly flour it and roll through the machine again. Repeat two more times.

Roll the dough through successively smaller settings until approximately 1/16 inch thick and at least 24 inches long. (Flour the dough if it seems sticky.) Lay out the pasta sheets in a single layer on a flat surface and let dry for 1 hour.

To prepare filling & assemble lasagna: Preheat oven to 375 degrees F. Grease a 9-by-13-inch baking dish with butter.

Whisk broth and mascarpone in a medium saucepan over medium-low heat until smooth, about 5 minutes. Add thyme, oregano and salt.

Heat the remaining 1 tablespoon butter in a large skillet over medium heat. Add spinach and cook, stirring, until wilted, 2 to 3 minutes. Remove from heat.

Cut the pasta into approximately 8-inch rectangles (you'll need at least 12). Arrange 3 of the rectangles crosswise in the prepared pan. Top with 1/4 cup of the spinach and 3/4 cup vegetables. Pour 1 cup of the mascarpone mixture over the vegetables and top with 1/3 cup farmer's cheese. Repeat to make 4 layers. Tuck any pasta edges into the sauce. (The lasagna will be very wet when it goes into the oven.)

Bake the lasagna until the top is golden brown and the edges are bubbling, 50 to 60 minutes. Let stand 20 minutes before serving.