In a saucepan, add all the tangerine curd ingredients and whisk well till combined.
Cook over medium-high heat, stirring constantly with a wooden spoon or heat-proof spatula (be sure to scrape sides of the pan), until the mixture is thick, 8 to 10 minutes. Let mixture come to a rapid simmer and cook, continually scraping sides of pan, for 2 minutes.
Remove saucepan from heat. Cover with plastic wrap, pressing it directly onto the surface of the curd to prevent a skin from forming.
Preheat oven to 150°C (300°F). Trim the edges of pastry to form a circle and place on the mini pie pan.
Pour the tangerine curd into the pans and bake in the oven for about 10 - 15 minutes.
Remove from the oven and let it cool completely.
Combine mascarpone cheese, vanilla, and heavy cream in a large bowl; beat with an electric mixer until smooth and creamy.
Add the sugar gradually and keep mixing until frosting is smooth and stiff peaks form, about 5 minutes.
Spread over the tarts (don't forget that they have to be completely cool). Top with the blueberries.
You can store the tangerine curd in a mason jar in the fridge, up to 1 1/2 weeks.