Somewhere, probably, there’s a rule written down that goes something like ‘don’t eat all of the warm blue cheese sauce before you serve the roasted potatoes’. If there is such a rule, I ignored it because the sauce is fantastic.
For the potatoes: Preheat the oven to 425 degrees F.
Place potatoes into a large bowl. Toss with the olive oil, rosemary, lemon zest and juice and salt and pepper to taste.
Spread out onto a baking sheet and roast until tender, about 35 minutes, stirring once or twice. While the potatoes are roasting make the sauce (below).
Transfer potatoes to a large bowl or serving platter. Drizzle with the sauce. Garnish with the green onions, jalapeno, parsley and blue cheese crumbles.
For the blue cheese sauce
Melt butter in a medium saucepan over medium heat.
Whisk in the flour and continue whisking for 3 minutes or until the flour is cooked.
Add the rosemary and nutmeg.
Whisk in the milk. Reduce heat to low. Whisking occasionally, continue cooking until thickened, 5-10 minutes.
Remove from heat and stir in the blue cheese and green onions.