01 - Bring a large pot of salted water to a rolling boil. Cook tagliatelle or fettuccine according to package directions until al dente. Reserve 2 tablespoons of pasta water before draining. Set aside.
02 - In a skillet over medium heat, melt the butter. Add the crushed pretzels and brown sugar. Stir and toast for 3 to 4 minutes until the mixture is golden and aromatic. Spread onto a plate to cool and crisp.
03 - In a medium saucepan, combine the granulated sugar and water. Cook over medium heat, swirling the pan gently (do not stir) until the mixture achieves a deep amber hue, approximately 6 to 8 minutes. Remove from heat. Carefully whisk in the heavy cream, butter, and sea salt; the mixture will bubble vigorously. Stir until smooth, then incorporate the vanilla extract.
04 - Add the drained pasta to the saucepan containing the salted caramel sauce. Toss gently to coat the noodles evenly. If a silkier sauce is desired, add a small amount of the reserved pasta water to achieve the desired consistency.
05 - Divide the caramel-coated pasta among individual serving bowls. Sprinkle generously with the prepared pretzel crunch. For an enhanced finish, garnish with flaky sea salt, additional crushed pretzels, or a dollop of whipped cream, if desired. Serve immediately.