Chill bowl and beaters before starting. Whip heavy cream to soft peaks adding powdered sugar and vanilla while whipping. Turn off mixer.
In a separate small bowl soften gelatin in water; you need to warm this mixture to dissolve, about 3 seconds in the microwave. Don’t make it too hot. Cool slightly and drizzle into the whipped cream with mixer running. Beat to stiff peaks. This whipped cream will hold up for 1 to 2 days. Can be used to frost cakes or cupcakes as well.
Prepare muffin mix according to package instructions and drop dough into mini-muffin tins. Bake 14 to 16 minutes at 400°F. Remove and cool.
Cut each muffin in half crosswise. Put a small dollop of whipped cream on bottom half. Layer with strawberry slice and more whipped cream. Top with the muffin top. Holding the top, insert a toothpick to hold together. Stand upright on a platter and serve.