Step 1: In a small saucepan, combine strawberries and sugar. Cook over medium heat for 10 minutes, stirring occasionally, until strawberries break down and release juices.
Step 2: Strain strawberry mixture through a fine mesh sieve, pressing with a spoon to extract all liquid. Discard solids and set strawberry syrup aside.
Step 3: In a medium saucepan, combine milk, heavy cream, and strawberry syrup. Heat over medium-low heat until steaming but not boiling.
Step 4: Reduce heat to low and add white chocolate chips, vanilla extract, and salt. Whisk continuously until chocolate is completely melted and mixture is smooth.
Step 5: Continue heating for 5 more minutes, whisking occasionally, until hot chocolate is thoroughly heated and well combined.
Step 6: Pour into mugs, top with whipped cream, and garnish with fresh strawberry slices. Serve immediately.