To prepare the beet ravioli, slice the beet into very thin slices (less than 1/8 of an inch). It's easiest to do this with a mandolin, but a sharp knife will do the trick! Cut as many beet slices as you'll need to serve 2-6 ravioli per person, 2 beet slices per ravioli. (The pine nut cheese will yield enough for approximately 16 ravioli, but you can make half of that and then enjoy the cheese on top of salads or as a dip, too.) Whisk the oil, lemon, and salt together and pour into a shallow dish (such as a glass lock container). Add the beet slices, cover, and refrigerate for at least 2 hours or overnight.
To prepare the pine nut cheese, add all ingredients except for the water to a food processor or a high speed blender. Start by adding 1/4 cup water and blending the mixture on high speed. Add more water as needed as you go along; the goal is to have a mixture that resembles a thick, creamy hummus in texture. Stop often to scrape the bowl down as you go.
To prepare the basil oil, blend the basil, oil, and salt till the mixture is smooth.
To serve the ravioli, pat the marinated beet slices dry. Place one beet square on your prep surface and top it with 1 tablespoon of the pine nut cheese. Top the cheese with the other beet square and gently press the edges together. Arrange ravioli on a serving plate and drizzle them with basil oil, if desired.