Conchas (Pan Dulce or Mexican Sweet Bread)

Ingredients

• 3 tbsp warm water
• 2-1/2 tsp active dry yeast
• 1/2 cup melted butter
• 1 tbsp vegetable oil
• 1/3 cup white granulated sugar
• 3/4 cup evaporated milk (or whole milk)
• 2 tsp kosher salt
• 2 tsp pure vanilla extract
• 2 tsp ground cinnamon
• 2 large eggs (at room temperature)
• 4 cups all-purpose flour
• 1/2 cup unsalted butter (at room temperature)
• 2/3 cup white granulated sugar
• 1 cup all-purpose flour
• 1 tsp pure vanilla extract
• 1 tsp cocoa powder (or 2-1/2 tsp cinnamon)