set a rack in the top third of the oven and heat to 450

put the tomato, almonds, roasted red pepper, garlic, cayenne 1/4 tsp salt and a few grinds of black pepper in a food processor. process, scraping the bowl as needed until the mixture is somewhat smooth, about 1 minute. add the vinager and 1 tbs of olive oil and process until well incorporated. taste and add more salt if needed.

trim the ends off of each potato and cut the potatos crosswise into 1/8- to 1/4-inch slices. in a bowl toss the potatos with the remaining 3 ybs olive oil and 1 tsp salt to coat well. lay the slices in a single layer on a baking sheet. Roast the potatos, turning the slices with a spatula and rotating the baking sheet halfway through roasting, until golden brown, 20 to 30 minutes. let the potatoes cool slightly.

to serve, arrange the potato slices on a serving platter; blot with a paper towel if they look oily. top each slice with a generous 1/4 tsp of the romesco sauce (you may not use all the sauce). garnish each with a tiny pinch of lemon zest and a parsley leaf.

the sauce can be made upto 3 days ahead and refrigerated. before using bring it to room temp and stir well.