Preheat oven to 175°C / 350°F. Grease pan.
Mix batter: Whisk flour, sugar, baking powder, and salt. Add plant milk, oil, vinegar, and vanilla. Pour into pan.
Swirl: Mix swirl ingredients. Drop spoonfuls over batter and swirl with a knife.
Bake: 30–35 minutes, until a toothpick comes out mostly clean.
Glaze: Mix glaze ingredients and drizzle over warm cake.
