Cut pasta sheets into 1-by-2-inch pieces and pinch in the centers to make a bowtie shape. Cook pasta to al dente.
Meanwhile, simmer potatoes in milk along with garlic cloves and bay leaf, about 10 minutes. Add cod to milk mixture and simmer until tender, 5 minutes more. Puree mixture (use caution when blending hot liquids; see Cook's Note).
Smear some brandade across the bottom of each of 4 plates. Toss the farfalle with the marinara sauce and divide over the top of the brandade. Garnish with breadcrumbs, basil and a drizzle of oil.
When blending hot liquid, first let it cool for five minutes or so, then transfer it to a blender, filling only halfway. Put the lid on, leaving one corner open. Cover the lid with a kitchen towel to catch splatters, and pulse until smooth.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.