In a large skillet or saute pan over medium-high heat, combine the ground meat, onions, salt and pepper and cook until onions are very soft and meat is browned, about 4 minutes. Add the green onions, fennel fronds, and mint and cook for 2 minutes. Add the butter, crushed tomatoes and 1 cup of the water and cook until the flavors have come together and liquid is mostly evaporated, about 6 minutes. Add the remaining cup of water and bring to a boil. Add the rice, return to a boil, cover and cook until the rice is partly cooked and most of the liquid has evaporated, about 10 minutes. Set aside to cool, covered, for 30 minutes or until cool enough to handle. Once the filling has cooled, stir in the Parmesan.

Soak the grape leaves, in batches as used, in warm water. Line the bottom of a 9-inch square, 3-inch deep baking dish with 3 or 4 of the unrolled leaves. Preheat the oven to 400 degrees F.

Lay 1 grape leaf on a plate, vein side up. Pinch off the thick stems where the stem joins the leaf. Take 2 teaspoons of the meat mixture and press it into a small sausage shape. Center it across the bottom edge of the grape leaf, positioning the filling where the stem was attached. Fold the lower left and right edges of the leaf towards the center, up and over the stuffing. Fold the upper left and right edges of the leaf forward so that all edges are in line with the edges of the stuffing below. Then, working carefully, roll leaf upwards, rolling to contain the stuffing as tightly as possible, to form a neat package. (The rolled grape leaf should look like a small cigar.) Place the rolled grape leaves, seam side down, in the prepared baking dish, packing them as tightly as possible into a snug layer. Try to fill as much of the space as possible. When you have completed 1 layer, begin a second layer directly on top of the first and repeat until you have rolled all of the filling in grape leaves. You should have 2 complete layers of grape leaves. Drizzle the olive oil over the rolled grape leaves and add enough hot water to the baking dish to just cover the grape leaves. Cover with aluminum foil. Bake, checking periodically to monitor the water level. Once the water level has evaporated about halfway, after about 30 minutes, squeeze the juice of 1 lemon over the leaves. Replace the foil cover and continue to bake until the leaves are tender and the water has completely evaporated, about 30 minutes longer, for a total cooking time of about 1 to 1 1/2 hours, depending on your oven.

Remove the grape leaves from the oven and set aside to cool. Serve either warm or at room temperature.

Note: Any unused grape leaves may be stored in the refrigerator in the original packaging, wrapped with plastic wrap, for up to 1 month.