To prepare the curry roux, melt the butter in a small pot over medium-low heat. Once melted, whisk in the flour and cook until the mixture turns a golden brown, which should take about 10-12 minutes. Stir almost continuously to prevent burning, adjusting the heat as necessary. Add the curry powder and whisk well, cooking for an additional 30 seconds before removing from heat.

Next, bring a large pot of water to a boil for blanching the udon noodles.

In a separate pot, heat over medium-high heat and add a drizzle of oil. Once hot, add the sliced meat and sauté with a pinch of salt until just cooked through. Be careful not to overcook. Remove the meat and set it aside, draining any excess oil from the pot.

Lower the heat to medium and add another drizzle of oil if needed. Add the carrots and onions, sprinkling with a bit of salt. Sauté until the carrots are tender and the onions are softened.

Now, add the broth, instant dashi (if using), soy sauce, and mirin to the pot. Bring the mixture to a simmer. If using dark chocolate, add it along with the curry roux. If the roux has hardened, scoop a ladle of hot broth to loosen it until it becomes scoopable. Stir and simmer until the roux is fully incorporated and no lumps remain. You can use the back of a spatula to break apart any stubborn lumps.

Taste the curry and adjust the sweetness with honey to balance any bitterness from the spices, depending on the curry blend used. Let it simmer uncovered for about 3 minutes or until it thickens slightly. Check the consistency and adjust with more broth or hot water for a thinner soup or simmer longer for a thicker sauce.

Once the desired consistency is achieved, taste again and add any additional salt, soy sauce, or honey as needed. Reduce the heat to very low and return the cooked meat to the pot just to warm it through without overcooking.

A couple of minutes before the sauce is ready, blanch the udon noodles according to the package instructions (frozen udon usually only need about a minute to heat through). Drain the noodles.

To serve, divide the udon noodles among bowls and ladle the curry over the top. Garnish with chopped scallions and enjoy!