Place the prepared broccoli into a mixing bowl, add in the love oil & season to taste, mix well.
Place the seasoned broccoli into a large baking dish, spread it out evenly & roast in the oven for 18 minutes or until very lightly charred. Remove & lower the oven temperature to 180°c - 350°f.
Bechamel Sauce
Whilst the broccoli is roasting, add the unsalted butter to a large saucepan over medium-high heat, allow it to melt & start boiling. Add in the plain flour, mix well & cook for 1 minute until thick, stirring frequently.
Pour in half of the milk, mix to combine & cook for 1 minute until thick. Add in the remaining milk & cook for a further 1 minute until thick. Remove from stovetop.
Add in the matured cheddar cheese, gruyere cheese and season to taste, mix to combine until smooth.
Pour the bechamel over the lightly charred broccoli, spread it out evenly. Grate over more matured cheddar cheese to cover the surface of the bechamel & bake in the oven for 35 minutes or until golden on the surface. Remove & let cool for 10 minutes. Portion, serve & dig in.