Begin with the crust by creaming together the butter, sugar and vanilla in a stand mixer fitted with a paddle attachment until light and fluffy. Add in the flour, cornstarch and lemon zest and beat until incorporated. Turn dough out onto a clean surface and flatten into a 1-inch-thick disk, wrap tightly and refrigerate 1 hour or up to 2 days.

For the filling, combine all the ingredients and whisk until well incorporated. This can be stored tightly covered in the refrigerator up to 1 day. If making ahead of time, make sure to return to room temperature and stir well before using.

Preheat oven to 350°F. Grease an 8- to 9-inch fluted tart pan with removable bottom with cooking spray. Remove dough from refrigerator and let sit for 10 minutes or microwave 30 seconds. Knead dough into a smooth ball (it may seem crumbly at first ... keep going!)

Roll out crust on a floured surface into a ¼-inch-thick circle approximately 12 inches in diameter and place into tart pan, making sure the bottom corners of the tart pan are filled in and patch up any cracks with extra dough. Trim any excess dough (see note) and press sides until even all around. Refrigerate for 30 minutes. Place shell on a sheet pan and wrap bottom with foil in case of leaks. Par-bake for 20–25 minutes, or until golden brown.

Remove from oven and carefully pour liquid lemon mixture into crust (it’s OK if the crust is warm out of the oven). Return to oven for 5 minutes. Pull oven shelf slightly out of oven and add small scoops of raspberry jam into the lemon filling in dollops to your liking (do not swirl). Bake tart for 18–22 minutes, or until there is a slight jiggle in the center (like Jell-O is perfect!). Let cool completely and unmold from tart pan onto a serving plate. Slice and serve with a dollop of whipped cream or extra raspberry jam and enjoy!

Note: Any extra dough can be rolled out to make shortbread cookie cutouts. Bake ¼-inch-thick cookies for 12 to 14 minutes at 350°F.