Place almonds in a 9-inch pie pan. Bake in a 300° regular or convection oven, shaking pan once, until nuts are golden, 10 to 12 minutes. Coat a 12-inch square of foil lightly with vegetable oil (about 1 teaspoon).
In an 8- to 10-inch frying pan over medium-high heat, combine sugar, butter, corn syrup, and milk. Stir occasionally until mixture is bubbly and golden, about 5 minutes. Add cocoa and stir until smooth, then stir in toasted almonds. Pour mixture onto oiled foil and spread about 1/4 inch thick. Let cool until solid, about 10 minutes. Break praline into 6 to 8 large chunks.