Sour Cream Layer Cake with Pecan Brittle

Ingredients

• vegetable oil spray nonstick
• 3/4 cup sugar
• 1/4 cup water
• 1/8 teaspoon cream of tartar
• 3/4 cup pecan halves toasted, coarsely chopped
• vegetable oil spray nonstick
• 18 1/4 ounces yellow cake mix I used Duncan Hinz 16.5-ounce
• 4 large eggs
• 1 cup sour cream
• 1/3 cup vegetable oil
• 1/2 teaspoon vanilla extract
• 1/2 teaspoon almond extract
• 2 ounces semisweet chocolate or bittersweet, coarsely grated, I used 3 ounces
• 1/2 cup dark brown sugar packed
• 3 tablespoons water
• 1/4 cup whipping cream
• 6 cups powdered sugar I used 4½ to 5 cups
• 1 cup unsalted butter room temperature