Heat your grill to a high setting. Halve any larger tomatoes. Tumble them on to a foil lined baking tray. Sprinkle with salt and slide under the grill for 5-10 mins, till the tomatoes have popped from their skins and softened. Leave to cool.
Roughly chop the sundried tomatoes. Pop them into a small bowl and cover with boiling water. Leave to soften. Bring a large pan of water to the boil.
Finely slice the kale leaves and stems, discarding any tough or woody ends. Add to the boiling water. Cook for 2 mins, drain and refresh under cold water. Squeeze the kale to remove as much excess water as possible.
Tip the penne into a large pan and cover with boiling water. Add a pinch of salt. Bring to the boil and simmer for 8-10 mins till the pasta is al dente (soft with a slight bite).
While the pasta is cooking, heat a small frying pan. Tip in the pine nuts. Toast for 2-3 mins till golden. Transfer to the bowl of a food processor.
Peel and finely chop the garlic. Zest and juice the lemon. Add them and the dry kale to the processor with the pinenuts. Tear in half the bunch of mint. Pour in 2 tbsp olive oil. Whizz till smooth. Add a little of the sundried tomato water if you like, to loosen the pesto. Taste and season.
Drain the pasta and tip back into the pan. Drain the sundried tomatoes. Add them to the pasta. Stir through the kale pesto. Gently fold through the grilled popped tomatoes. Roughly tear the remaining mint and add that. Spoon into warm