Preheat the oven to 200°C (400°F). This high initial heat encourages quick caramelization on the tomato surfaces without drying them out completely—concentrating sweetness and building deeper flavor.

Core and halve the tomatoes. If using very large tomatoes, quarter them. Place cut-side up on a rimmed baking sheet lined with parchment. Drizzle evenly with 2 tablespoons olive oil and scatter 1/2 teaspoon kosher salt over them. Arrange in a single layer so each piece roasts rather than steams; roasting concentrates tomato sugars and breaks down cell walls so the jam will set more quickly.

Roast the tomatoes for 35–45 minutes, until the edges are caramelized and the centers are softened. Roasting at this stage browns the tomato sugars (Maillard and caramelization) which adds complexity and reduces the raw tomato acidity.

While the tomatoes roast, finely dice the onion and mince the garlic. Heat a medium heavy-bottomed saucepan over medium heat and add the remaining 1 tablespoon olive oil. Add the onion and 1/2 teaspoon salt and sweat gently for 6–8 minutes until soft and translucent—this builds a sweet savory base without browning which helps keep the jam bright.

Add the garlic and smoked paprika to the onions and cook for 30–45 seconds until fragrant—briefly to bloom the paprika and release its smoky oils but not so long that the garlic goes bitter.

Transfer the roasted tomatoes (including any juices and the small caramelized bits on the tray) into the saucepan with the onions. Break up large pieces with a spatula or wooden spoon; the roasting step made them soft so they’ll mash easily. Return the pan to medium-low heat.

Stir in the granulated sugar and the remaining 1/2 teaspoon kosher salt. The sugar both sweetens and helps the jam set by binding water as it dissolves; adding it now lets it dissolve into the warm tomato juices rather than burning on a hot pan.

Bring the mixture to a gentle simmer, then lower the heat and simmer uncovered for 20–30 minutes, stirring every few minutes to prevent sticking. You're looking for a thick, glossy consistency that coats the back of a spoon. Slow evaporation concentrates flavor and allows pectin naturally present in tomatoes to gel slightly; stirring prevents scorching.

If you want a smoother jam, pulse the mixture 3–4 times in a food processor or use an immersion blender briefly. Pulse rather than fully puréeing to keep some texture—restaurant jams often balance silkiness with small pieces for interest.

Swirl in the butter off the heat until melted and glossy, then taste and adjust seasoning with black pepper and up to a pinch more salt. The butter (or olive oil if you prefer) rounds out acidity and gives the jam a luxurious sheen similar to a restaurant finish.

Transfer the jam to a warm sterilized jar and let cool to room temperature. The jam will thicken a bit more as it cools. Store refrigerated for up to 10–14 days. Serve at room temperature to let the flavors and texture shine.

Serving suggestions: spoon onto toasted baguette slices and top with ricotta or goat cheese; serve alongside roasted meats or grilled fish; stir a spoonful into braised beans or use as a glaze for roasted vegetables.