Preheat the oven to 350°F (180°C). Line a 9-inch x 5-inch pound cake pan with parchment paper. Spray the sides and bottom of the pan with cooking oil spray. Set aside.
In a large mixing bowl, add self-rising flour and sugar. Whisk to incorporate.
Fold in yogurt, melted plant-based butter, and vanilla extract if used.
Stir with a rubber spatula until the batter is smooth and consistent.
Pour the batter in the prepared loaf pan.
Bake the pound cake in the center rack of the oven at 350 °F (180 °C) for 50-60 minutes. Cover the top of the pan with foil after 40 minutes to prevent the top of the cake from darkening too fast.
Check if it is ready by inserting a toothpick in the center of the pound cake. If it comes out clean, it means you can remove the pan from the oven. If not, bake longer, in 10-minute increments, until the crumb is set.
Let the pound cake cool down in the pan at room temperature for 10 minutes, then on a cooling rack at room temperature for 1 hour before serving.
