The recipe is below is written to make the crust, the raspberry curd filling and the finished tart all in one day. However, the tart crust and raspberry curd can be made one day in advance and the tart assembled and baked the next day.
For the Crust
Adjust 1 oven rack to the middle position in the oven. Preheat the oven to 350 degrees.
Melt the butter is a small saucepan. While the butter is melting, whisk the flour, sugar, and salt together in a bowl. Add melted butter while it is still very warm and stir with a silicone spatula or wooden spoon until a dough forms and there are no visible bits of flour left. Using your hands, press two-thirds of dough into the bottom of 9- inch tart pan with removable bottom. Press remaining dough into fluted sides of the pan. Press and smooth dough with your hands to even thickness.
Place pan on a wire rack set in a rimmed baking sheet and bake on the middle rack, until crust is deep golden brown and firm to touch, 25-30 minutes, rotating pan halfway through baking. Set it aside until it is ready to fill with the raspberry curd filling. If making one day in advance, allow it to cool completely and then cover with a plastic wrap.
For the Raspberry Curd
Place the raspberries, 1/4 cup of sugar and 2 tablespoons of water in a 3-quart non-reactive saucepan. Cook the raspberries over medium heat until they start to break down. Use a potato masker to completely break down the berries Strain the berries through a fine mesh strainer to remove the seeds. Allow the raspberries to cool to room temperature. Add the lemon juice and remaining 1/4 cup of sugar and taste the mixture. If it is still a little tart add additional sugar 2 tablespoons at time until desired sweetness is reached.
Place the raspberry puree back in the 3-quart saucepan. Rinse and dry the bowl and place it next to the stove with a medium-coarse strainer. Add the whole eggs and egg yolks to the raspberry-lemon mixture and whisk to combine.
Cook the curd over medium-low heat, stirring constantly with silicone spatula or metal whisk, until the mixture is thickened and registers 180 degrees in multiple spots, 5 to 7 minutes.
Remove the saucepan from the heat and whisk in butter, 2 tablespoons at a time until incorporated. Strain curd through the medium-coarse strainer into the bowl to remove any solids.
If making the curd one day in advance, press a piece of plastic wrap directly onto the surface of curd and refrigerate until ready to use. (Curd can be refrigerated for up to 3 days.)
Finishing the Tart
Immediately scrape the raspberry curd into the tart crust and bake in a 350°F oven until the curd is firm to the touch, 15-17 minutes. If making the ingredients one day in advance, add 2-3 minutes to the baking time of the tart. This additional time is needed because the curd will be cold and will need additional time to come to temperature.
Remove the tart from the oven and allow it to completely cool before decorating with fresh berries. If serving the tart the next day, refrigerate the tart, remove from the refrigerator and decorate with the fresh fruit.
The raspberry curd can be made with frozen raspberries. Add the frozen berries, sugar, and water to the pan and start cooking while the berries are still frozen. Start on medium-low heat to allow the berries to defrost and cook without burning them.