Place the cashews in a small bowl with 2 cups of boiling water for 1/2 hour.
Prepare the topping: Place the lemon juice, maple syrup, cinnamon, and nutmeg in a large shallow dish and mix well. Add the sliced pears and gently coat well.
Prepare the crust: Oil a 9-inch tart pan. Place the pecans in a food processor and process until finely ground. Add the dates, cinnamon, and cardamom and pulse-process until the ingredients are just ground up. Do not over-process or your crust will be too gummy.
Transfer to the tart pan and press down firmly to create the crust. The mixture should be holding together. If not, return to the processor and process a bit further. Depending upon the moisture of the dates, you may need to add a small amount of water or liquid from the topping to help hold the crust together.
Prepare the cashew cream: Drain and rinse the cashews well. Place them in a strong blender along with 1/2 cup of water and 2 T. maple syrup. The amount of water you will need will depend on the strength of your blender. Blend until creamy and thick as whipped cream. If too grainy, strain cream through a fine sieve.
Spread an even layer of the cream over the crust. Creatively place the pear slices on top of the cream. Try forming a spiral where each pear slice slightly overlaps the one next to it.
Decorate with fresh berries and mint leaves. If you have more time, chill for 15 minutes or m ore before serving.