Meanwhile, we start on our filling. In a large saute pan we heat the olive oil over medium-low heat. We put our clean mushrooms in our food processor and pulse until they are minced nicely but not a wet mess. We add our onions to the pan and cook, stirring occasionally, for about 5 minutes. We want them tender and golden. While the onions are cooking, we mince the garlic with a little kosher salt. We add the garlic when the onions are ready and cook for another minute. Lastly, we add the minced mushrooms and cook for a few minutes over medium heat. We taste and adjust for salt and pepper. When the mushrooms have released their liquid, we turn off the heat and reserve until we are ready to fill the lasagne.
When the water is boiling for the pasta, we add the 18 lasagne noodles from the package. We stir and cook for about 10 minutes. We want the noodles just al dente. We actually should have cooked the noodles a bit longer, but we drained them before we realized it! When the noodles are drained, we spread them out, without rinsing, on wax paper, in one layer. The noodles are hot and we let them cool a couple of minutes before doing this.
We are now ready to combine the cheeses. Over a piece of wax paper, we grate the mozzarella using our box grater. We put the shredded mozzarella into a large bowl. The small pieces of mozzarella that did not quite get shredded we put into a small cup and reserve. We combine the shredded mozzarella, Locatelli, and ricotta cheese in the bowl. We add the cooled mushroom mixture and the fresh herbs. We also add some freshly ground black pepper, stir, and taste for seasoning (it’s delicious!)
Next we coat the bottom of a 13 × 9 inch baking pan with some tomato sauce. We place a couple of large spoonfuls of the mushroom-cheese filling down the center of each lasagne noodle. We are only filling 16 of the noodles to leave some for the children (we re-boil the remaining two for them). When the filling is divided as evenly as possible, we spread it almost the length of the noodle with a spoon and then roll up. We place it in the prepared baking dish, standing curly-side up, and continue with the rest of the rolls. We cover the rolls with a little of the tomato sauce and the reserved mozzarella. We place the pan, uncovered, into the oven and bake for 20 minutes to heat through. We should have actually covered the pan so the rolls wouldn’t get dried out on the ends but they were still wonderful! On the “30 Minute Meals” show, Rachael had rolled up the hot noodles around a hot filling and then just broiled the top to melt some cheese. Since we undercooked our noodles we needed to bake them in the oven, but we’ll try this next time!
We remove the bubbling pan from the oven and after a couple of minutes carefully serve the lasagne with additional hot tomato sauce.