For the onion, cut the onion in half so that the root is still intact. Shave off the very bottom of the root and the very bottom of the top talk, so that the onions will sit without rolling.
Cut the onion halves four times (like a pizza), but be sure not to cut all the way through.
Bake at 425F until onion is tender, about 40 minutes. (If you want yours a little more charred, turn on the broiler for the last 5 minutes.)
For the potatoes, toss in olive oil, salt and pepper. Roast with the onion for the last 25 minutes.
For the sauce, heat butter over medium heat. Add minced garlic and sauté until fragrant.
Add flour and stir to combine. Cook until roux is formed and begins to turn tan.
Raise heat to medium-high and whisk in milk until all clumps are gone.
Add the herbs, reduce the heat to medium and cook until sauce has thickened to desired level.
Season to taste with red pepper, salt and pepper. Set aside on low heat.
For the kale, heat 1 t olive oil large sauté pan over medium-high heat.
Add the kale and sauté unit wilted. Finish with the lemon juice, salt and pepper to taste.