Preheat oven to 450°.
Toss the rutabaga with a pinch of salt and a tablespoon of olive oil. Roast until soft, about 30–45 minutes.
Caramelize the onion: Heat butter in pan and slowly cook the onion for 5 minutes. Add thyme, garlic and a pinch of salt and continue for another 5 minutes or until the onion is soft and caramelized.
Add the roasted rutabaga and beet greens and cook (medium) until greens are wilted. Add cream, mustard and cheddar and bring to a soft boil for 2–3 minutes. Take off heat and let cool. This can be done a day ahead.
Transfer rutabaga to 2 individual ramekins (7- to 9-inch diameter). Brush the edges with butter and fit puff pastry. When ready to serve, preheat oven to 400°. Place ramekins in the oven and bake until puff pastry is golden and crisp. Serve immediately.
Note: This recipe also works with other root vegetables, including beet, parsnip, sweet potato, turnip, sunchoke, (watermelon, black or white) radish. Even better, make this with a mix of root vegetables!
PAIRING SUGGESTION: New Braunfels Brewing Co. “Les Fleurs du Mal.” Undergoing a second and third fermentation with wild yeasts, locally sourced lemongrass and Texas wildflower honey, this beer blooms into a lively tart and deliciously honeyed expression of the Texas Hill Country. Bet you can’t drink just one!