Use a 9” diameter tart pan with a removable bottom. Line bottom with parchment cut to fit, and lightly spray with oil.
Preheat oven to 350 degrees
Using a food processor, combine crust ingredients and pulse until the mixture is crumbly.
Firmly press the mixture into the bottom and up the sides of the pan. The flat bottom of a cup or glass helps to distribute mixture evenly as you’re pressing down.
Bake for 12-15 minutes, until crust is lightly browned.
Cool pan on a wire rack before filling.
For the Filling & Garnish
Prepare garnish by cooking oats in 1 teaspoon coconut oil in a small skillet over low heat. Stir constantly until oats are toasted, about 3 minutes. Gradually add half of the sugar, stirring constantly, until sugar is melted. Remove from heat and add the remaining sugar and stir to coat. Season with a pinch of kosher salt. Let cool.
Add cocoa powder to bowl of food processor. Pour in espresso liquid and let sit for 5 minutes.
Add melted chocolate, agave, vanilla, 2/3 cup melted coconut oil and salt. Process until mixture is very smooth and thick, about 30 seconds.
Pour filling into the cooled crust. Smooth the top and lightly tap on a flat surface to remove air bubbles. Chill for 15 minutes.
Scatter the oat garnish over the top of the tart, sprinkle with the salt flakes, and refrigerate at least 30 minutes until filling has set.
Remove the tart from the pan to a serving plate. Cut the chilled tart with a hot, dry knife.
