Start by boiling water and cooking the whole-grain farfalle until it is al dente. You will know it is ready when it is tender but still has a bit of a bite. Rinse it under cold water afterward to stop the cooking. Avoid overcooking, as that can make it mushy.
Heat up some oil in a pan and add the sliced baby portobello mushrooms, garlic, and red onion. Sauté until the mushrooms are browned and fragrant, which should take about 7-10 minutes. Be careful not to overcrowd the pan; otherwise, they will not brown nicely.
Once the mushrooms are looking good, sprinkle in the Italian seasoning and toss in the grape tomatoes. Cook until the tomatoes soften a bit, which should take about 5 minutes. Do not skip the seasoning or the salad may lack flavor.
While the veggies are cooking, whisk together the cashew mayo, Dijon mustard, maple syrup, and white balsamic vinegar in a bowl. The dressing should come together smoothly and have a pleasant tang. If it is too stiff, a little water can help.
In a large bowl, mix the pasta, sautéed veggies, and drained cannellini beans if you are using them. Add in the dressing and stir gently until everything is coated, taking care not to break up the pasta.
Sprinkle fresh dill and parsley on top for a pop of color and added flavor. Serve the salad warm or chilled, based on your preference. Do not let it sit too long before serving, or it may get soggy.