Wrap tofu in paper towels and put some weight on it, such as a large can; leave that be while you attend to other things, 5 to 10 minutes.
Cook the broccoli and cauliflower florets in a steaming basket, until cooked about halfway through. Fill a large bowl with cold water and ice cubes and plunge your cauliflower and broccoli in that cold bath to stop the cooking process. Leave them in there for 2-3 minutes then drain.
Cut your tofu into ½ inch cubes. Drizzle a little bit of olive oil in large skillet and heat over medium high heat. When it’s really hot throw in the tofu cubes and cook for 2-3 minutes per side, until nice, crispy and golden on all sides. Set aside.
Meanwhile, in a large saucepan, heat the oil over medium heat and sauté the onion until translucent. Add garlic, salt, pepper and flour, stir to cook the flour, 2-3 minutes.
Add milk, about ½ cup at at time, whisking until well incorporated with each addition. Bring to a boil, whisking constantly. Reduce heat and continue whisking for about 5 minutes. Remove from heat and whisk in Dijon mustard, white wine vinegar and tahini.
Gently fold in broccoli, cauliflower, tofu and 50g hazelnuts.
Transfer to a large oven safe baking dish, or 4 individual.
Grind remaining 25g toasted hazelnuts and buckwheat groats in a coffee grinder of mini food processor.
Sprinkle that mixture overtop your casserole. Place in the oven and bake for 20-25 minutes, until top starts to color.
Notes
*This is another dish that I did pre-Lent, but it could very easily be made grain free by using a non grain flour instead of whole wheat flour.