Heat olive oil in a medium saucepan set over medium-high heat.
Add blanched almonds, chopped hazelnuts and bread pieces. Cook, stirring frequently, until bread is lightly toasted and nuts are golden brown.
Transfer nuts and bread to the bowl of a food processor. Pulse until finely chopped.
In the same saucepan set over medium heat, heat olive oil. Add garlic and sauté for 30 seconds. Stir in diced tomatoes and cook until tomatoes start to thicken, 7 to 10 minutes.
Transfer to the food processor, along with roasted red peppers, sherry (or red wine) vinegar, salt and chile flakes. Process until well combined.
With the motor running, slowly pour in the olive oil until the mixture is smooth.
Present the crown roast of pork on a serving platter, surrounded by the vegetable paella. To serve, remove the string and cut between the ribs. Serve with paella and Romesco sauce.