Valentine's Day Tsunami Cake - Milk

Ingredients

• 3/4 cup (180 mL) unsalted Ontario butter, room temperature
• ​1 1/2 cups (355 mL) granulated sugar
• 3 large eggs, room temperature
• 3/4 cup (180 mL) vegetable or canola oil
• 1 tablespoon (15 mL) pure vanilla extract
• 2 1/2 cups (590 mL) all-purpose flour
• 2 1/2 teaspoons (12.5 mL) baking powder
• 1 teaspoon (5 mL) salt
• 1 cup (240 mL) Ontario buttermilk
• 1/2 cup (120 mL) unsalted Ontario butter, room temperature
• 2 cups (475 mL) powdered sugar, or to taste
• 1 teaspoon (5 mL) pure vanilla extract
• 2 tablespoons (30 mL) Ontario whipping cream
• Food colouring, optional
• 1 1/4 cup (300 mL) + 1/2 cup (120 mL) Ontario whipping cream
• 1 1/4 cup (300 mL) Ontario whole milk
• 1/3 cup (80 mL) cornstarch
• 1 1/4 cup (300 mL) sweetened condensed milk
• 1 teaspoon pure vanilla extract