Bring a large pot of generously salted water to a boil.
Add the pappardelle and cook according to package directions until al dente (usually 6-7 minutes).
Meanwhile, melt the butter in a small skillet over medium-low heat. Let it cook for a minute or two until the butter is just lightly golden colored (don't let it go too long, or the butter will burn!). Immediately add the sage to skillet and let it sizzle for a second, then turn off the heat. Squeeze the lemon juice into the skillet and swirl to combine. Set the pan aside off of the heat.
When the pasta is done cooking, reserve 1/2 cup of the cooking liquid, then drain the pasta in a colander.
Put the drained pasta back in the pot and place it on the stove over medium-low heat. Pour roughly 1/4 cup of the reserved cooking liquid over the pasta, and then pour the brown butter sage sauce over the top. Stir gently to combine, and let it cook, stirring constantly, for about 1 minute, until the sauce nicely coats all noodles.
Divide the pasta up into two serving bowls and top each one with freshly grated Parmesan cheese, cracked black pepper, and Maldon sea salt. Serve right away.