Servings: 12 to 24

1 cup (20g) basil leaves 1 cup (20g) basil leaves
1/2 cup (120g) whole milk ½ cup (120g) whole milk
1/2 cup (120 g) half and half ½ cup (120 g) half and half
3/4 cup (150g) granulated sugar ¾ cup (150g) granulated sugar
1/4 cup (36g) all-purpose flour ¼ cup (36g) all-purpose flour
1/4 tsp salt ¼ tsp salt
1 cup (227g) unsalted butter, at room temp. 1 cup (227g) unsalted butter, at room temp.
1 tsp pure vanilla extract 1 tsp pure vanilla extract
green food coloring (optional) green food coloring (optional)
 
Chocolate Ganache Chocolate Ganache
10 oz (283g) semisweet or bittersweet chocolate, finely chopped 10 oz (283g) semisweet or bittersweet chocolate, finely chopped
1 cup (240g) heavy cream 1 cup (240g) heavy cream

Combine the basil leaves, milk, and half and half in medium saucepan. Heat gently over medium heat until just simmering, then remove from the heat. Let cool and then refrigerate for at least 2 hours and up to overnight. Remove the basil leaves from the cream, and then squeeze the leaves over the cream. Discard the leaves.
In a medium bowl, whisk together the sugar, flour and the salt really well (the sugar will help keep the flour from lumping when it boils, so spend a good minute really whisking it together.) Place the mixture in a medium, heavy-bottom saucepan. Slowly pour the basil cream into the flour, whisking to combing as you pour. Cook over medium heat; stirring constantly with a whisk, until the mixture comes to a gentle boil (periodically run a spatula round the edges of the saucepan to remove any flour lurking there.) Reduce the heat slightly nd continue to whisk and occasionally stir until the mixture has thickened considerably, 2 to3 minutes. Remove from the heat and continue stirring for 30 seconds.
Transfer the mixture to a bowl and cover with plastic wrap, making sure the plastic sits directly on the surface (this will help keep it from forming a skin.) Let cool to room temperature.
When the mixture has cooled, place the butter in the bowl of a stand mixer fitted with a paddle, and beat on medium speed until smooth and creamy, scraping down the sides as needed. Start adding the flour mixture a few spoonfuls at a time, mixing on low speed after each addition, until it is all incorporated. Scrape down the sides and mix on medium speed until the buttercream is light and fluffy, 2 to 3 minutes. Add the vanilla and food coloring, if using, and mix on low speed until combined.
For the Ganache
Place the chocolate in a small bowl. Heat the heavy cream in a small saucepan until it is simmering and just about to boil. Pour the cream over the chocolate, cover the bowl with plastic wrap, and let sit for 5 minutes. Remover the plastic and whisk until completely smooth. Let cool to room temperature.
To Assemble
Spread the basil buttercream evenly on top of the chilled brownies. Return the pan to the refrigerator and chill for 1 hour. Pour the cooled ganache over the top of the chilled buttercream and using an offset spatula, spread it in a eve layer. Return the pan to the refrigerator for 1 hour.
Remove the pan from the refrigerator and let sit for 10 minutes before cutting, to all the glaze to soften slightly. Cut into bars and serve. Store brownies in an airtight container in the refrigerator for up to 3 days.