Broccoli and blue cheese or dill is one of my favourite winter soups, so I thought I'd try all 3 ingredients together in tart form. I found this needed an eggier custard than I usually use, probably because of the moisture from the broccoli and the creamy cheese. It's important to let it cool to just barely warm before serving to allow the custard to fully set. It reheats well, too. —MaryMaryCulinary
Combine flour and salt in a food processor and pulse to combine. Add butter and pulse until it is broken up and partly incorporated. When some pieces are tiny, but some are still the size of peas, it is ready.
Add 3 tablespoons water and pulse. You do not want the pastry to form a ball in the food processor. Open it and grab a handful of the crumbs. If you can squeeze them to form a ball it is ready. If not, add more water in small increments.
Flatten dough into a disc and wrap in plastic. Refrigerate for a few hours.
Roll dough on a lightly floured surface to a 13" circle. Transfer to a 9" or 10" springform pan/deep tart pan/deep dish pie plate. If using a springform, trim dough so it is 2" high. If using a tart pan, trim dough so edges extend just past top of dish. Chill for 30 minutes.
Preheat oven to 375F. Place a greased sheet of foil (greased side down) over pastry and fill with dried beans. Bake for 15 minutes. Remove foil and beans carefully and bake crust for another 10 minutes or so, until set and pale golden. Set aside to cool on a rack while you prepare filling.
Broccoli, blue cheese and leek filling
Blanch the broccoli florets for 3-4 minutes* in boiling salted water. Drain and rinse well with ice water to stop the cooking. Drain again and blot dry with paper towels. Set aside. *You don't want crunchy broccoli here--I like mine tender but still firm.
Heat butter over medium-low heat and add leeks, along with a pinch of salt. Saute until very tender but not browned, about 10 minutes. Set aside to cool slightly.
Beat eggs, cream, dill, 1/4 teaspoon salt and a generous grinding of pepper together. Spread leeks evenly in bottom of tart shell, cover with broccoli florets and top with cheese. Carefully pour custard mixture over top (I do this while it's in the oven to minimize spilling).
Bake at 375F for 40-50 minutes. I mistakenly used a 9" pan for mine, so it took the longer time. When done, the centre will still be a bit wobbly, but it will set as it cools.