Preheat the oven to 450F.

Place the milk in a bowl and microwave on high for 2 minutes, or until warm to the touch. Sift the flour, salt, and baking powder together in a large mixing bowl.

Crack the eggs into the work bowl of an electric mixer fitted with a whisk and beat on medium speed for about 3 minutes, until foamy and pale in color. Turn down the mixer to low and add the warm milk.

Gradually add the flour mixture and beat on medium speed for about 2 minutes. Turn the machine off and let the batter rest for 1 hour at room temperature.

Spray a popover tin generously with nonstick spray. Fill the popover cups almost to the top with the batter and place the popover tin on a cookie sheet. Transfer to the oven and bake for 15 minutes.

Turn down the oven temperature to 375F and bake for 30 to 35 minutes longer, until the popovers are a deep golden brown on the outside and airy on the inside. Turn out the popovers and serve hot with strawberry butter.