Heat the oil in a large saucepan with a tight-fitting lid over medium heat.
In a medium bowl, toss together with salt, pepper, and flour.
Dredge beef cubes in the seasoned flour, shaking off excess; add to the saucepan and cook until browned on all sides.
Remove beef cubes to a paper towel lined plate.
To the same saucepan, add the onion and garlic; cook until onion is soft then add the wine and whisk up all of the browned bits from the bottom of the saucepan.
Return browned beef cubes to the saucepan; bring to a boil then reduce heat, cover and simmer for 25 minutes.
Next, add the broth and sweet potatoes to the saucepan; cover and cook for 45 minutes, stirring occasionally, until beef is fork-tender.
Add kale, thyme (and additional broth if needed); cover and cook for 10 minutes. Garnish with parsley before serving.