In an oven-proof dutch oven, with a tight fitting lid, heat vegetable oil over medium-high heat. Season steak with 1 teaspoon salt and 1 teaspoon black pepper. Place in dutch oven and cook on all sides until browned, approximately 2 - 3 minutes per side.
In a medium bowl, mix together the A.1., jam, 3/4 cup water, garlic, mustard, brown sugar, lemon zest and lemon juice. Pour over steak, cover, and place in preheated oven. Bake for 2 hours, until steak is fork tender. Remove steak to a large plate, cover with foil and let rest. Place the dutch oven with juices on stovetop over medium heat. Remove approximately 1/2 cup of juice to heat-proof bowl, whisk in the potato starch, pour back into dutch oven; stir to combine. Heat sauce until thickened, approximately 2 minutes; keep warm.
Using two forks, shred the steak into bite-sized pieces; keep warm.
Bring milk and remaining 1 1/2 cups water to boiling in a large saucepan over high heat. Add in the garlic powder, remaining 1/4 teaspoon salt and remaining 1/4 teaspoon black pepper. Gradually stir in the polenta and cook, stirring constantly, for approximately 3 minutes until thickened. Stir in the parmesan cheese and butter.
To serve, spoon polenta into a serving bowl, top with shredded steak and gravy and enjoy!