Preheat oven to 350 degrees.
Butter a 9 inch round tart pan. With a stand or handheld mixer, beat together the butter, 1/3 cup sugar and 1/4 teaspoon salt until fluffy (about a minute).
Add the 3 whole eggs one at a time, mixing each in fully before adding the next one. Scrape sides of bowl if needed during mixing.
Add 1/2 teaspoon vanilla extract and lemon zest and mix in.
Add almond meal and mix just until combined; do not over mix.
Using a spatula, scrape the sides and bottom of the bowl to ensure all ingredients are mixed together. Pour the batter into the prepared tart pan, scraping all batter from the bowl.
Spread batter in tart pan to cover the bottom and up on the sides to the top of the pan creating a cavity. It will not be stiff batter and will not stay fully up on the sides though the cavity will remain intact. Place in the refrigerator while you prepare the filling.
Whisk together crème fraiche, 2 egg yolks, 1/2 teaspoon vanilla, 3 tablespoons sugar, 1/8 teaspoon salt, cardamom and nutmeg. Pour into the cavity of the crust batter. Smooth out with a spatula allowing a border of crust batter to be between the side of the tart pan and the filling which will form a bit of a rim.
Place the pear slices in the filling in any decorative pattern you choose.
I suggest putting the tart on a cookie sheet to bake to stabilize getting it into and out of the oven (I also used a tart pan with a removable bottom so there was a bit of leakage). Place the tart in the oven and bake until slightly golden, about 35 minutes. Serve warm.