Preheat oven to 350°F (175°C). Line two 4-inch tart rings with parchment paper and place them on a baking sheet.
In a mixing bowl, combine the oat flour, almond flour, maple syrup, coconut oil, and vanilla extract until it forms a soft dough. Press the dough into each tart ring, first press into the bottom to make a thin layer, and then shape the sides. Try to make it thin as you don’t want a crust too thick.
Bake for 10-15 minutes, depending on the thickness until the crust is golden brown. Remove from heat and let it cool completely before removing the crust from the tart rings.
Preheat oven to 350°F (175°C). Line a 7×6-inch baking pan with parchment paper.
In a mixing bowl, combine the oat flour, coconut sugar, cocoa powder, almond milk, and oil. Melt the dark chocolate over a double boiler. Once melted, pour into the batter and whisk until fully combined.
Pour the batter into the prepared baking pan (you should have a thickness of about 1/4-inch) and bake for about 15 minutes. Remove from heat and let cool completely.
Cut two circles of brownie large enough to fit into the bottom of the crust. If you prefer a thinner layer of brownie, feel free to flatten it. You will have extra brownie, just eat it or save for later.
Place the dark chocolate chips or chunks in a small bowl. Heat the almond milk in a saucepan over medium heat. As soon as it starts to boil, remove from heat and pour over the dark chocolate. Whisk for a couple of minutes, or until the chocolate is fully melted and combined with the almond milk. Let it cool for 10 minutes before pouring into the tartlets, over the brownie layer. Refrigerate for about 2 hours, or until the ganache has set.
Salted Caramel Chocolate Frosting
Place the 1/2 cup coconut cream and coconut sugar in a small saucepan. Heat over medium heat and bring to a simmer. Let simmer for about 8 minutes. Remove from heat and stir in the vanilla extra, sea salt, and dark chocolate chips. Stir until the chocolate has melted. Next, add the 1/4 coconut cream and stir to combine. Transfer to a bowl, cover with plastic film and refrigerate for at least 2 hours, or until the frosting has set.
Transfer the frosting to a piping bag and pipe rounds on each tartlet (see photos). Top with crushed hazelnuts or almonds and enjoy!
These tartlets will keep in the refrigerator for up to 3 days. Let sit on the counter for 10 minutes before serving.