To prepare peppers: Preheat oven to 400 degrees F. Halve peppers lengthwise through the stems, leaving them attached. Remove the seeds. Lightly brush the peppers outside and inside with oil; sprinkle the insides with salt and pepper. Place, cut-side down, in a 9-by-13-inch baking dish. Bake until peppers are just tender, 10 to 15 minutes. Let cool slightly. Turn cut-side up.

To prepare filling: Bring 2 cups salted water to a boil in a large wide pan. Stir in kale, cover and cook until tender, 10 to 12 minutes. Drain, rinse under cold water; squeeze dry. Finely chop.

Heat oil in a large nonstick skillet over medium heat. Add onion and chopped bell pepper; cook, stirring often, until onion is golden, 6 to 8 minutes. Add garlic and cook, stirring, for 30 seconds. Stir in the kale. Remove from the heat and let cool slightly. Stir in rice, Parmesan, 2 tablespoons pine nuts and lemon juice. Season with salt and pepper. Divide the filling among the pepper halves. Sprinkle with the remaining 2 tablespoons pine nuts.

Add 2 tablespoons water to the baking dish. Cover the peppers with foil and bake until heated through, 15 to 20 minutes. Uncover and bake for 5 minutes more. Serve hot.

Tips: To cook brown rice: Place 1 cup brown rice, 21/2 cups water and a pinch of salt, if desired, in a medium saucepan; bring to a simmer. Cover; cook over low heat until rice is tender and most of the liquid has been absorbed, 45 to 50 minutes. Makes 3 cups.

To toast pine nuts: Heat a small dry skillet over medium-low heat. Add pine nuts and cook, stirring constantly, until golden and fragrant, 2 to 3 minutes. (Or spread in a small baking pan and bake at 400 degrees F for about 5 minutes.)

MAKE AHEAD TIP: Prepare through step 3, cover and refrigerate for up to 2 days.