If you are making your puff pastry, make 30 minutes ahead of time. In a food processor, add all of the dry ingredients and the butter. Pulse until combined and looks like sand, but not too much so that it combines. Then add the water, just enough so that it clumps together. Then remove from the processor, wrap in plastic wrap and place in the refrigerator for 30 minutes (or longer). You can roll it out and fold it up again, refrigerating one or two more times, but I don't worry about that for this recipe. The flavor is amazing and it works perfectly for this tart (and saves time). What saves even more time is to buy puff pastry, and you can do that as well. Roll it out when you have prepared the ingredients for the tart.
Preheat the oven to 390 degrees Fahrenheit (or 200 celsius).
Bring a medium pot of water to boil. While waiting for it to boil, trim the bottoms of the asparagus (about 1/2 - 1" taken off). Then place all of the asparagus into the boiling water to blanche them, about 4-5 minutes. Remove and place on a paper towel to train. Set aside four full spears that will be added to the food processor for the spread. The rest of the asparagus can be sliced length-wise in half once cooled to add to the top of the tart.
In a food processor, add the four spears you set aside (chop them roughly before adding), add the garlic (peeled, but not chopped), egg, Parmesan and 150g of the ricotta (save the rest of the ricotta for dabbing on top later). Pulse until smooth. Add lemon juice, salt and pepper. Taste. Adjust by adding more of the latter three ingredients as desired.
Sauté the sliced spring onions in a small skillet with a tab of butter or olive oil. Cook for about 5 minutes until translucent over medium heat. You can either add these to the spread in the food processor, or simply add them to the top of the spread with the courgettes and sliced asparagus. Cook's choice!
Rolling out the tart to the size desired - rectangular, round or square - decide whether you will make a rough tart - no pan and simply rolled out onto parchment, or will be placing in a tart pan, as this will determine how precise you need to roll it out. I prefer this tart being placed directly onto the parchment but you can put it in a tart pan and dress it up a bit, absolutely :),
To add a bit of an edge to your tart if placed directly on the parchment, trim off about 1 cm from the pastry and place on top of the entire edge all the way around to give a bit of height and distinction.
Then using a spatula, spread the asparagus mix you processed in the food processor or blender across the top of the pastry from corner to corner.
Be generous with the amount of courgettes and asparagus you add to the top of the spread. In my opinion, the photo you see skimps on vegetables and I would have enjoyed more with each bite. Layer on the finely sliced courgettes (keep the skin on when you slice as it adds color to the dish), blanched asparagus and spring onions (if not added to the spread already), and then add the remaining ricotta in dollops over the vegetables. Season with salt and pepper and drizzle with olive oil. Brush the edges of the pastry with egg wash if desired.
Bake for 25 minutes or until the edges of the tart are nice and brown. Serve warm and enjoy with a crisp glass of white wine. (This dish is also wonderful cold, so perfect for leftovers.)