Preheat oven to 425 degrees. Prepare all ingredients. Place potatoes in a bowl and toss with 2 tsp Old Bay Seasoning, 6 sliced garlic cloves, salt, freshly ground pepper and 2 T olive oil. Place on a parchment lined sheet pan, bake for 15 minutes. Remove from oven and turn potatoes. In the same bowl you tossed the potatoes, toss the sausage, leeks or scallions with a bit more olive oil and an additional 2 tsp Old Bay Seasoning. Place on sheet pan with potatoes, return to oven and bake for 10 -15 more minutes. Check and remove from oven when desired crispiness of potatoes and sausage. Set aside and keep warm.
In the meantime melt the butter. Add 1 T Old Bay Seasoning, 1/2 tsp smoked paprika, pinch of red chili flakes, 2 minced garlic cloves, Chardonnay, lemon zest, salt and pepper to the butter, let cool. Brush some of the mixture on corn and toss the remaining with the cleaned shrimp. On another parchment lined sheet pan place the corn and shrimp. Cook in oven for 5-8 minutes until shrimp are done, turn half way through, watch carefully not to overcook, they will turn pink when done. You may need to remove shrimp and return corn a few more minutes.
Place all romesco ingredients in blender - blend until smooth, taste and adjust seasoning if needed. Serve on crostini alongside the sheet pan bake.
To serve, arrange ingredients on one or two sheet pans, garnish with fresh squeezed lemon juice, chopped parsley and chives, or arrange on a large platter and garnish. Serves 4-6.