Chocolate Crust
9 ounces (255 grams) chocolate wafers (such as these; the cookie portion of these are best for homemade crumbs)
6 ounces (170 grams) bitter- or semisweet chocolate, coarsely chopped or 1 cup chips
1/2 cup (95 grams) packed dark brown sugar
7 tablespoons (100 grams) unsalted butter, melted and still hot

Fudge Layer
1 cup (235 ml) heavy or whipping cream
13 ounces (370 grams) bittersweet or semisweet chocolate, chopped
2 tablespoons (30 grams) smooth peanut butter (optional)

Cheesecake Layer
2 8-ounce packages (455 grams) cream cheese, at room temperature
1 1/4 cups (320 grams) smooth peanut butter
1 cup (200 grams) granulated sugar
3/4 cup (180 grams) sour cream
3 large eggs
2 teaspoons (10 ml) vanilla extract

Ganache Topping
1/3 cup (80 ml) heavy or whipping cream
4 1/2 ounces (130 grams) bittersweet or semisweet chocolate, chopped
1 tablespoon (15 grams) smooth peanut butter (optional)