We are sadly at the tail end of the too-short English asparagus season. I like to peel the asparagus for this pretty tart. It is a lot of work, but worthwhile, as once cooked, they just melt in your mouth. If you cannot find white asparagus, use all green.
For the pastry:
175g butter, softened
250g plain flour
2 tbsp milk
Pinch of salt
for the filling:
3 large onions, sliced
1 large bunch white asparagus
1 large bunch green asparagus
4 tbsp sunflower oil
3 tbsp caster sugar
Sea salt, rainbow pepper
Make the pastry by mixing all the ingredients quickly to form a ball. Use it to line a dish either round (24cm) or rectangular (20cm x 10cm). Cover with cling wrap and refrigerate until needed. Remove from the fridge 15 minutes before using.
To make the filling: fry the onions in the sunflower oil, starting with a high heat for about two minutes and then reducing it when they start to brown. When golden brown, add the sugar and continue to cook until the onions are caramelised. Season to taste.
Wash the asparagus, cut off the tough stalks, and starting about 2cm from the tip, peel them. Bring a pan of water to the boil and steam them until soft. Place on kitchen towel to absorb excess moisture.
Heat your oven to 200°C and blind bake the tart base for 10-15 minutes. It should feel sandy and turn white but lightly brown-beige at the edges.
Remove from the oven and spread with the onions. Lay the white and green asparagus on top to make a pretty pattern. Season with sea salt and rainbow pepper and return to the oven for 10 minutes.