Bring a large pot of salted water to a boil. Cook the ravioli according to package directions until al dente. Drain the ravioli.Meanwhile, cook the bacon in a large skillet over medium heat until crisp. Drain onto a paper towel. Wipe the skillet clean, then set back over medium-high heat. Add the olive oil. When the oil shimmers, add the Brussels sprouts and season with salt and pepper. Cook until the sprouts are crisping on the edges, 3 to 4 minutes. Add the shallots, cooking another 2-3 minutes, until caramelized. Remove the Brussels sprouts from the skillet to a plate. It's OK if some of the shallots are left behind in the skillet.To the same skillet, melt together the butter and nuts over medium heat, cooking until the butter begins to brown, about 3-4 minutes. Reduce the heat to low, add the apple cider, thyme, and lemon zest. Season with salt, pepper, and crushed red pepper flakes. Drop the ravioli into the sauce, gently tossing to combine. Divide the ravioli between plates and top with the crispy Brussels sprouts, bacon, and cheese.