Arge's "You'll think you died and went to heaven" Dark Chocolate & Peanut Butter Cheesecake

Arge's "You'll think you died and went to heaven" Dark Chocolate & Peanut Butter Cheesecake

2 cups graham cracker crumbs
3 tablespoons granulated sugar
7 tablespoons unsalted butter, melted
3-8oz. packages cream cheese, at room temperature
10 oz. dark chocolate, melted and cooled
2 tablespoons all-purpose flour
Salt
1 1/4 cups sugar
1/3 cup creamy peanut butter
1 tablespoon vanilla extract
4 large eggs, at room temperature
3 oz. chopped semisweet or bittersweet chocolate
5 tablespoons unsalted butter
1 tablespoon light corn syrup
Cocoa powder, for garnish

Position a rack in the center of the oven and heat the oven to 375°F.
In a medium bowl, stir together the graham cracker crumbs and 3 tablespoons sugar. Mix in the melted butter until the crumbs are evenly moist and clump together slightly. Transfer the mixture to a 9-inch springform pan and press evenly onto the bottom and about 2 inches up the sides of the pan (to press, use plastic wrap or a flat-bottom measuring cup). Bake until the crust is fragrant and slightly darkened, 9 to 12 minutes. Let the pan cool on a rack. Lower the oven temperature to 300 degrees.
In a stand mixer fitted with the paddle attachment, beat the cream cheese, melted dark chocolate, flour and a pinch of salt on medium speed, scraping down the sides of the bowl and the paddle frequently, until very smooth and fluffy, about 5 minutes. Make sure the cheese has no lumps. Add the 1 1/4 cups of sugar and continue beating until well blended and smooth.
Add the peanut butter and vanilla and beat until blended, about 30 seconds. Add the eggs one at a time, beating just until blended. (Don’t overbeat once the eggs have been added or the cheesecake will puff too much and crack as it cools.) Pour the filling into the cooled crust and smooth the top.
Bake at 300 degrees until the center jiggles like Jell-O when nudged, 55 to 65 minutes. The cake will be slightly puffed around the edges, and the center will still look moist. Set on a rack and cool completely. Cover and refrigerate until well chilled, at least 8 hours and up to 3 days.
In a small bowl, melt the 3 oz. chopped chocolate and the butter. Add the corn syrup and whisk until smooth. Unclasp and remove the side of the springform pan and run a long, thin metal spatula under the bottom crust of the cheesecake. Carefully slide the cake onto a flat serving plate. Pour the ganache on the cheesecake and spread evenly.
Garnish with cocoa powder sifted over the cake and serve immediately.