Add the olive oil to a medium pot over medium heat. When warm, add the garlic and salt. Stir to coat and cook for 2 minutes, or until just starting to soften.
Add the broth and raise the heat to high. When the broth starts to boil, turn down the heat to medium so it simmers.
Add the potatoes. Cook for about 15 minutes, stirring occasionally, or until soft when poked with a knife.
Stir in the frozen veggies and marinara sauce. Simmer for another 4-6 minutes or until the vegetables are soft.
Season to taste with salt and pepper. Add Parmesan cheese if desired. Serve warm.
Notes
Store leftovers in an airtight container for up to 5 days in the fridge. Warm in a small pot or in a heat-safe bowl in the microwave, adding more broth if desired.