Preheat the oven to 350° Fahrenheit. Grease the bottom of an 11" tart pan and lightly sprinkle with some flour. Be sure not to grease the sides of the tart pan as this will interfere with the batter rising.
Making The Batter
Use a large mixing bowl and a hand mixer and beat the softened butter, sugar, vanilla extract, and salt together on high speed until smooth. About 2-3 minutes.
Reduce the speed to low and add in one egg at a time. Allow each egg to fully incorporate into the batter before adding the next egg.
Slowly add the milk into the batter. Beat on low until the milk is well combined.
Add the flour and baking powder to the batter and continue to beat on low speed. Use a spatula to scrape the sides. Beat until the dry ingredients are well combined.
Baking The Cake
Pour batter into the tart pan. Use a spatula to spread the batter evenly.
Bake for 20 minutes. Remove from the oven and transfer onto a cooling rack. Remove from the tart pan and allow it to cool completely.
Making The Filling
Use a medium mixing bowl and combine instant pudding with heavy whipping cream. Use a hand mixer and whisk until the mixture is creamy. Set aside.
Making The Glaze
Use a small bowl and whisk 1 tablespoon cornstarch with ¼ cup of water until there are no lumps. Set aside.
Use a small saucepan and bring a ¼ cup of water and ½ cup of sugar to a boil. Once the water has reached a boil, reduce the heat to medium and whisk in the liquid cornstarch into the boiling sugar water.
Whisk continuously for about 3-5 minutes until the mixture becomes thick and syrupy. Remove from heat and set aside.
Once the cake has fully cooled. Spread the pudding cream mixture with a spatula or cake spreader evenly across the cake.
Top the filling with sliced strawberries. Use a pastry brush to glaze the strawberries. Allow to harden for 30 minutes.