Grease a 6 inch cake pan. Place a circle of parchment paper in the bottom.
In a medium bowl, toss strawberries in 1 tbsp flour and 1 tbsp sugar. Add strawberries to pan in an even layer.
In a medium bowl, beat egg. Whisk in butter, 1/3 cup sugar, and vanilla until smooth. Add remaining ingredients, including remaining flour, except water. Pour batter into pan over strawberry layer.
Add water to the Instant Pot® and insert steam rack. Lower cake pan onto steam rack. Lock lid.
Press the Manual or Pressure Cook button and adjust time to 35 minutes. When timer beeps, quick-release pressure until float valve drops. Unlock lid.
Remove cake pan from pot and transfer to a cooling rack to cool for 30 minutes. Flip cake onto a serving platter. Remove parchment paper. Slice and serve.