Step 1: Preheat your oven to 400°F (200°C). This is crucial for roasting the broccolini to perfection.
Step 2: In a mixing bowl, toss the chopped broccolini with olive oil, salt, and black pepper until evenly coated. Spread the broccolini on a baking sheet in a single layer. Roast in the preheated oven for about 15 minutes, or until the edges are crisp and the stems are tender. Stir halfway through to ensure even cooking.
Step 3: While the broccolini is roasting, spread softened unsalted butter on one side of each slice of bread. This will create a beautiful golden crust when grilled.
Step 4: On the unbuttered side of half of the bread slices, layer shredded or sliced cheddar cheese, followed by the roasted broccolini. Top with another slice of bread, buttered side facing out.
Step 5: Heat a skillet or griddle over medium heat. Once hot, carefully place the sandwiches in the pan. Cook for about 3-4 minutes on each side, or until the bread is golden brown and the cheese has melted.
Step 6: Remove the sandwiches from the skillet, slice in half, and serve immediately. Enjoy your delightful Roasted Broccolini Grilled Cheese with a side salad or your favorite dipping sauce.