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You can use the bowl of your stand mixer, if you have one. If you don't have a stand mixer, use a regular mixing bowl. Choose a mixing bowl that’s relatively deep so you can combine the ingredients with ease. If you’re using a stand mixer, use the whisk attachment. A handheld mixer or manual whisk will also work fine. Whip thoroughly for 1-2 minutes until stiff peaks form. To check for stiff peaks, lift the whisk out of the bowl. This will cause the cream to form a peak. If the peak holds its shape, it's stiff. If it falls in on itself after a couple of seconds, whip for 1 more minute. Spoon the sour cream into the bowl with your cream mixture. Whisk the ingredients together gently until thoroughly combined. Place the remaining ingredients into the bowl with the cream mixture. Use a large spoon to combine the ingredients thoroughly. Don’t use your mixer or whisk for this part! Transfer the ambrosia salad to a large glass serving bowl. Cover the bowl with plastic wrap and place it in your fridge. Chill the salad for at least 2 hours before serving. Store any leftovers in an airtight container in the fridge. Be sure to consume your ambrosia salad within 3 to 5 days.

Summary:
Place the heavy cream and sugar into a large bowl. Whip the cream and sugar until stiff peaks form. Add the sour cream to the bowl and whisk. Stir in the marshmallows, fruits, coconut, and pecans. Cover the ambrosia salad and refrigerate for 2 hours. Serve the ambrosia salad cold.