Preheat the oven to 180 degrees celsius.
Grab a medium sized baking tray and place the peeled and quartered parsnips into the tray, pour over the olive oil and toss until coated in oil. Pop into the oven for 30 mins, turning after 15 mins.
Find a heavy based medium saucepan and put on a medium heat. Add the butter and remaining parsnips to the pan and cook for a few minutes or until the parsnip starts to turn golden.
When the parsnips have a lovely colour, pour in the milk and cream. Turn the heat down low and put a lid on the saucepan and let simmer. Check and stir occasionally.
Meanwhile, grab a small bowl and add your olive oil and lemon juice. Grate in the zest of half a lemon. Finely chop the parsley and garlic, add to your bowl and stir all ingredients to combine. Taste the gremolata and season with salt and pepper.
Now check your parsnip puree to see how tender the parsnips are, it should take 25-30 mins for them to soften. Once your parsnips can be easily pierced with a fork, remove the saucepan from the heat. Carefully pour the contents of the saucepan into a blender or food processor. Blend until silky smooth. Taste your puree and season with salt and pepper.
By now, your roasted parsnips should be golden and ready to serve.
Find a nice plate and dollop your puree into a big mound in the centre. Using the back of a spoon, push the mixture towards the edge of the plate, creating a little well in the centre. Pile your roast parsnips in the middle of the plate and spoon gremolata across the parsnips.