Preheat the oven to 350°F/ 180°C. Trim the sprouts and peel off any old leaves. Shred finely using a mandolin, food processor, or roughly chopped with a sharp knife. Roughly chop the kale.
Finely dice the shallot and crush the garlic. Place a large frying pan over medium-high heat. Add the butter to the pan and saute the shallot until softened. Add in the crushed garlic, kale, and Brussels sprouts. Stir and saute for a few minutes.
Grate the cheese on the large side of a box grater. Grate the lemon zest with the small side of a box grater. Add 1/2 cup grated cheese, heavy cream, and lemon zest to the greens. Stir through. Taste and season as necessary.
Transfer the creamy greens to an oven-proof dish and spread evenly along the base. Mix the almond flour and the remaining 1/2 cup grated cheese in a bowl. Sprinkle over the top of the greens and season with more cracked black pepper.
Roast in the center of the oven for 12-15 minutes until the top is golden and crisp. While the greens are in the oven, wipe out the frying pan and fry the pancetta lardons until cooked through and crispy. Transfer to a plate with kitchen paper used to absorb the excess grease. Sprinkle the lardons over the baked grain and serve.