Heat the oven to 350 degrees F. Line an 8-inch square pan with parchment paper. Lightly brush the parchment paper with butter or spray with cooking spray.
Melt the butter in a medium saucepan over medium heat. Remove from heat and immediately add the chocolate, Herbie's Spice Dust and cocoa powder. Whisk until smooth.
In a large mixing bowl, whisk the eggs, sugar, vanilla and salt to form a slightly thick mixture. Add the tahini and whisk to combine. Now fold in the flour, stir until just incorporated (do not over-stir). Reserve half of the tahini mixture in a separate bowl for later. Add the melted chocolate mixture to the remaining tahini mixture, stir until batter is well combined.
Pour the batter into the prepared pan. Spread evenly. Spread the strawberry jam evenly over the top of the chocolate layer
With a spoon, dollop the reserved tahini mixture over the top. With the tip of wooden skewer, swril the tahini dollops into the strawberry jam layer.
Place the pan on the middle rack of the 350 degrees F heated-oven. Bake for 30 minutes, until the edges are set but the center remains slightly moist.
Remove from the oven and sprinkle with rose petals. Cool in the pan for 30 minutes. Lift the parchment edges up carefully to transfer the brownies from the pan. Cool for another 30 minutes. Cut into 2-inch squares.