Treat your veg like you would treat an expensive piece of meat
This Romanesco I pickled, sweated, grilled, blanched and sautéed to experiment. For this dish I decided blanched was the best.
There are many ways to treat a veg and make them shine. I found below list by Brownble.com which sums up the Cheffie techniques for home cooks really nicely. Get yourself an armfull of a veg and test all methods. Great experiment: but an armfull of for instance broccoli and test all techniques on them. The only technique she does not mention is pickling, which I find a great way to add sour, sweet and crisp. Full article you can find here.
Steaming: Retains the most nutrients out of all the cooking methods. In this technique you place your foods in a steamer basket with some seasonings if you'd like, over a pot of boiling water. You cover the pot and cook the veggies until tender. It happens fast, which is why it's a great method for nutrient retention
Boiling: Cooks harder vegetables like potatoes and foods like pasta and noodles. In this technique you drop the food into salted boiling water and cook it until tender.
Simmering: Cooks foods in water, broth or a sauce but at a lower temperature than boiling. In this technique you can bring the liquid quickly to a boil and then lower the heat to reach a simmer, in which you'll see slight movement of the liquid and some bubbles but not as much as with boiling.
Sautéing: Cooks foods in a pan while tossing, to create a nice golden color in the exterior of the food. You can do this with some kind of oil or non-dairy butter or also try dry sautéing without any oils. The food cooks quickly as it's directly exposed to the heat in the pan, and therefore it retains crispness, and the vibrant colors of the veggies pop!
Braising: Perfect for one pot meals and infusing a ton of flavor into your dish. In this technique you start by sautéing your vegetables, adding spices and seasonings and then adding a liquid for the foods to simmer in for the remaining cooking time. Foods get golden in the first stage and tender and flavorful in the second stage.
Roasting: Where many veggies shine sky high! Roasting is basically cooking your vegetables in the oven, usually at a temperature of 400ºF- 425ºF (a bit higher than what you'd bake a cake at). This method caramelizes the natural sugars in food and makes the flavors really come out to play. It's probably one of my preferred methods for many of these favorites:
Grilling: There's nothing like an open grill for that perfect char and smoky flavor, and yes, you can barbecue your heart out even if you're cooking vegan food! In this technique you'll be getting a nice char on your foods by cooking them on a gas or charcoal grill, and you can even use an indoor cast iron grill pan
Stir-frying: Cooks food in a wok on very high heat with a bit of oil and requires constant tossing. In this technique you're quickly moving the food around in a wok and the result is vibrant colors, a slight smoky flavor, and the perfect combination of tenderness in the vegetables while still maintaining crispness.
Sweating: Similar to sautéing but done at a very low heat to extract as much flavor as possible from the food.