Preheat your oven to 400°F (200°C). In a large bowl, toss the potato cubes with olive oil and a generous sprinkle of salt. Spread the potatoes in a single layer on a baking sheet, allowing enough space between each piece for even roasting.

Bake the potatoes for 30-35 minutes, flipping them halfway through, until they are golden and crispy on the outside and tender inside. Roasting brings out the natural sweetness in the potatoes, creating a crisp exterior essential for Patatas Bravas.

While the potatoes roast, heat 1 tablespoon of olive oil in a small saucepan over medium heat. Add the finely chopped onion and sauté for about 5 minutes, until softened and translucent. This forms the base for the bravas sauce.

Add the minced garlic to the saucepan, stirring for about 30 seconds until fragrant. Next, add the smoked paprika, cayenne pepper, and sweet paprika, mixing well to bloom the spices and bring out their full flavour.

Add the tomato paste to the pan, stirring for 1 minute to combine with the spices. Then pour in the crushed tomatoes and broth, stirring until smooth. Let the sauce simmer for 10-15 minutes, allowing it to thicken and develop a robust, spicy flavour.

Season the bravas sauce with salt to taste and stir in a teaspoon of sherry vinegar if you like a bit of tang. Once the sauce reaches your desired consistency, remove it from the heat. Set aside to cool slightly.

In a small bowl, combine the mayonnaise, minced garlic, lemon juice, and a pinch of salt to make the optional aioli. Mix well, adjusting the garlic level to your taste. The aioli provides a creamy contrast to the spicy bravas sauce.

To serve, arrange the crispy potatoes on a serving plate and spoon the warm bravas sauce generously over them. Add dollops of the aioli (if using) on top or alongside. Garnish with a sprinkle of chopped parsley for a fresh touch, and serve immediately while the potatoes are hot and crisp.