Preheat your oven to 350°F (175°C).

In a medium bowl, combine the graham cracker crumbs and granulated sugar.

Pour the melted butter over the mixture and stir until the crumbs are evenly coated.

Press the crumb mixture firmly into the bottom and up the sides of a 9-inch tart pan.

Bake the crust for 8-10 minutes, or until it’s golden brown. Let it cool completely.

In a medium saucepan, melt the butter over medium heat.

Add the dark brown sugar and stir until it dissolves and begins to bubble, about 2-3 minutes.

In a small bowl, whisk together the heavy cream, cornstarch, and salt until smooth.

Slowly add the cream mixture to the saucepan, whisking constantly to prevent lumps.

Continue to cook, whisking frequently, until the mixture thickens, about 5-7 minutes.

Remove the pan from the heat and stir in the vanilla extract.

In a separate bowl, lightly beat the egg yolks. Slowly add a small amount of the hot butterscotch mixture to the yolks, whisking constantly to temper them.

Gradually add the tempered egg yolks back into the saucepan, whisking continuously.

Return the saucepan to medium heat and cook for an additional 2-3 minutes, until the filling is thick and smooth.

Pour the butterscotch filling into the cooled crust and spread it evenly.

Chill the tart in the refrigerator for at least 4 hours or until set.

In a large bowl, beat the heavy cream, powdered sugar, and vanilla extract with an electric mixer until stiff peaks form.

Spread the whipped cream over the chilled tart or pipe it decoratively.

Slice the tart and serve chilled.

Optionally, garnish with butterscotch chips, caramel drizzle, or a sprinkle of sea salt.