Make the cupcakes. Preheat the oven to 350℉. Line a 12-count cupcake or muffin pan with foil cupcake liners and set aside.
In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, salt, and cinnamon until combined. Set aside.
In a separate medium bowl, whisk together the melted butter and sugar until well combined. Whisk in the egg, whole milk, sour cream, and vanilla extract.
Slowly whisk the dry ingredients into the wet ingredients until fully combined. The batter will resemble a thick pancake batter.
Spoon the batter into the prepared cupcake tins, filling each ¾ of the way full. Bake for 14 to 16 minutes, until an inserted toothpick comes out clean.
Let the cupcakes cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely, about 1 hour.
Make the milk mixture. In a large bowl, whisk together the evaporated milk, sweetened condensed milk, and whole milk.
Poke holes all over the tops of the cupcakes with a skewer or toothpick. Slowly spoon about 1 tablespoon of the milk mixture over each one, let it soak in, and repeat until each cupcake gets about 3 tablespoons. For less mess, you can use a squeeze bottle or small syringe to inject the milk instead, spreading it out over 5 to 6 small injections per cupcake.
Cover the cupcakes with plastic wrap and refrigerate for at least 2 hours, or up to overnight, so they fully soak up the milk mixture.
Make the whipped topping. Whip the heavy cream, powdered sugar, and vanilla extract with a stand mixer using the whisk attachment or an electric hand mixer on medium-high speed until stiff peaks form, about 2-4 minutes. Spread it onto the cupcakes with an angled spatula, or transfer it to a piping bag and pipe it on.
Dust the cupcakes with ground cinnamon, top each with a slice or two of fresh strawberries, and serve.
Notes
Storage: Keep leftovers covered in the fridge for up to 3 days.
Make ahead: You can bake and soak the cupcakes up to 2 days ahead. Keep them covered in the fridge and add the whipped cream right before serving.
Freezing: Freeze the baked cupcakes, wrapped well, before adding the milk for up to 3 months. Thaw them completely, then soak and top as usual.
Foil liners: Foil holds up better than paper when the cupcakes sit in the milk for a few days, so I'd stick with foil if you're making them ahead.