The last two weeks have sent us a clear message: autumn has arrived. And with the chillier weather comes the end of tomato season. Many who grow in polytunnels may be wondering what to make with the last bit of their harvest – maybe you have lots of unripened tomatoes and you're not sure what to do with them; or perhaps you have too many tomatoes and need to preserve them. Here's a delicious recipe that will use up the last of your harvest, whether they're green or red.

Romesco sauce is a Spanish creation which originates in Catalonia. It combines fresh roasted vegetables with almonds and tart sherry vinegar. It's kind of like a pesto – it has a thick consistency – but with a completely different flavour.

I like to make a large amount (triple this recipe) and preserve the sauce by putting it in sterilised jars before boiling the filled jars to seal. The jars of sauce will keep up to two months, if preserved well. Just store it in a dark, cool place. I eat romesco sauce with roasted vegetables (such as cauliflower). It's a great addition to soups, makes a lovely salad dressing when thinned out with olive oil and is delicious on grilled meats or fish.

Romesco sauce

Serves 12

Ingredients:

1 red bell pepper, seeded & cut in half lengthwise

1 head of garlic with the top cut off (use a serrated knife)

4 medium sized vine tomatoes, cored (or smaller tomatoes, whole)

125g blanched, whole almonds, lightly toasted

1 red chili pepper, seeded and sliced in half lengthwise

1 tsp minced garlic

1-2 heels of stale bread, ripped into chunks

1 tbsp sherry vinegar

1 heaping tsp paprika

4 tbsp olive oil, plus more for drizzling

salt and pepper, to taste

Directions:

1. Preheat the oven to 190°C. Line a baking sheet with parchment and set aside.

2. Prepare the vegetables: core the tomatoes, seed and slice the peppers and cut the head off the garlic (you can save the little bits of garlic in the head for the minced garlic needed later).

3. Place the head of garlic, peppers and tomatoes on the baking sheet. Season with salt and pepper and drizzle with olive oil. Roast for about 40 minutes. They should be really well roasted when done.

4. Toast the almonds on the stove top (put them in a dry pan and toss until they're evenly toasted). Set aside.

5. In a blender or food processor, add the olive oil, almonds, bread, minced garlic, vinegar, and paprika. Pulse a few times to start breaking things down.

6. Add the roasted garlic, tomatoes and peppers. Pulse until smooth. The consistency should still have some texture to it; similar to pesto.

7. Season with salt and pepper. Serve warm or at room temperature with all kinds of meat, white fish, grilled veggies or even just some nice, crusty bread, warmed olives and manchego cheese.