Preheat the oven to 350℉ and set the rack to the middle position. Spray a 9-10-inch tart pan with a removable bottom with cooking spray.
In a mixing bowl, combine 1 1/2 cups of almond flour, four tablespoons of cornstarch, 1/4 cup of sugar, 1/2 teaspoon of salt, 1/2 teaspoon of cardamom, and four tablespoons of melted butter. Use a spatula, pastry blender, or clean hands to mix the dough until it comes together.
Spread the shortbread crust evenly over the bottom of the pan and slightly up the sides. Use your fingers to move it into place, and then the bottom of a flat cup to press it down. Bake the shortbread crust for 15-20 minutes, checking it around 15 minutes to ensure it doesn't burn. Remove the crust from the oven and let it cool completely before adding the filling.
While the crust cools, make the custard filling by creaming together 1/4 cup of softened butter and 1/4 cup of sugar with a mixer. Then add a pinch of salt, the egg, almond extract, and two tablespoons of cornstarch. Mix for about 45 seconds or until the custard is smooth and fluffy.
Slice the pears into thin slices.
When the shortbread crust is cool to the touch, gently spread the custard filling evenly over the top. Layer the pears over the filling, starting at the outer crust and then creating a smaller circle in the center.Bake the tart for 30 minutes. About 10 minutes before the tart is finished, gently brush some warm honey mixed with one teaspoon of water over the pear slices to help them brown a bit.
Let the tart cool to room temperature before cutting.
Notes
Store leftovers in the refrigerator for up to two days. If desired, make the shortbread crust a day in advance. Cover and refrigerate it until ready to fill.