Place the blueberries and sugar in a 4-quart saucepan. Zest the lemon on top of the sugar. Juice the lemon and add 2 teaspoons of lemon juice to the blueberry mixture. Stir the ingredients together with a spatula to combine.

Heat the blueberry mixture over medium high heat until it comes to a boil. Reduce the temperature to medium and cook the blueberry mixture until the liquid is reduced by about a third and is noticeably thicker. Occasionally stir the blueberries to keep them from sticking and to ensure they don’t burn. It will take about 15-17 minutes.

Remove the blueberries from the heat and pour the blueberry compote into a heat proof bowl and allow it completely cool before adding it the whipped cream cheese.

The compote can be made a day ahead and refrigerated until ready to use.

Toast the rolled oats by placing them in a non-stick skillet and place the skillet over medium-high heat. Stir the oats frequently until they turn golden brown and smell nutty and toasty. Don’t let them burn. If they turn black either remove the black pieces or start over. Burnt oats will make the crust take bitter.

Place the oats, hazelnuts, brown sugar, salt, and cinnamon in the bowl of a food processor and process the ingredients until they resemble fine breadcrumbs.

Pour the mixture into a medium sized bowl. Mix in the melted coconut oil. Then add the honey and stir it in. The mixture should clump when you squeeze it together in your hand.

Press the hazelnut oat mixture into a 14x5-inch tart pan. Make sure the sides and ends are of of even thickness.

Place the crust in the freezer for an hour or in the refrigerator for at least two (2) hours. You can also make the crust the day before and refrigerator overnight.

Place the cream cheese, mascarpone, and sugar in a large bowl. Mix on medium-high speed with a hand mixer until the mixture appear creamy, about 30 seconds. Add the heavy cream and vanilla extract and beat on medium high speed until the beats leave tracks in the cream mixture and there are stiff peaks.

Add about 1/3 of the blueberry compote to the cream cheese mixture and streak the blueberry compote through the cream cheese.

Remove the tart from the refrigerator and carefully remove the sides of the tart pan. Fill the tart with the blueberry cream cheese mixture. Create swirls and peaks with an offset spatula o the back of a teaspoon.

Add dollops of the remaining blueberry compote on top or serve the compote with slices of the tart.

Refrigerate the tart until ready to serve. The tart should be consumed within 1 day of adding the cream filling because the crust will soften the longer the filling is in the crust.