Preheat your oven to 400 degrees Fahrenheit. While the oven is warming up, wash and dry your baby gold potatoes thoroughly. Cut them into halves or quarters so they are all roughly the same size, which ensures they cook evenly during the roasting process.
In a large mixing bowl, whisk together the Dijon-style mustard, heavy cream, olive oil, minced garlic, dried thyme, salt, and black pepper. Stir the mixture until it is smooth and the mustard is fully incorporated into the cream.
Add the prepared potatoes into the bowl with the mustard mixture. Use a large spoon or your hands to toss the potatoes until every piece is generously coated in the creamy sauce. The sauce will look thick, which is exactly what you want for a flavorful crust.
Spread the potatoes out in a single layer on a large rimmed baking sheet. Avoid crowding the pan, as this can cause the potatoes to steam rather than roast. Place them in the oven and bake for 40 to 45 minutes, tossing them halfway through, until the potatoes are fork-tender and the edges are golden brown and bubbling.
Remove the baking sheet from the oven and let the potatoes rest for a few minutes. This allows the creamy sauce to set slightly. Sprinkle the fresh chopped parsley over the top for a pop of color and a fresh finish before serving warm.
