Liz's Apple Crisp w/Vanilla Sour Cream

Here is my version of apple crisp. I hope you love it!
A few notes about my recipe:

• I do not peel my apples. I know this sounds crazy, but it saves lots of time and effort and the skins soften during the baking. Give it a try and see what you think. 
• Spreading your apples over a larger surface creates a greater topping-to-apple ratio. I use a 9x13-inch baking pan. If you prefer a more apples-to-topping apple crisp, bake your crisp in a 9x9-inch pan.
• When its apple baking time, I choose a variety of different apples to combine in my recipes. I combine varieties that are firm, soft, tart, and sweet all baked together under a pie crust or crisp topping. 
• Did you know that apple crisp can be baked and then frozen? You can also prepare several batches of the topping and freeze them to use any time you feel like making an apple crisp or other fruit crisp. 
• Change up your crisp! Take out 2 apples and replace with cubed and steamed sweet potato. Or, replace 2 apples with 2 cup frozen or fresh blueberries.
  
• One last tip, traditionally apple crisp is served plain but I love to serve it with a dollop of sweetened sour cream. However you prepare or serve your apple crisp remember to visit Hollis’ farmstands for the best apples in New Hampshire!  

Makes one 9x9-inch or one 9x13-inch crisp
½ cup dark brown sugar
1 ½ cups quick oats
1/3 cup flour
1 teaspoon cinnamon
1 teaspoon salt
4 ounces (1 stick) unsalted butter, cold
8 large apples-assorted types of apples. Combine varieties that are firm, soft, tart, and sweet.
1/3 cup sugar
1 tablespoon apple cider vinegar or lemon juice

Sour cream topping:
16 oz sour cream (whole fat-no skimping here!)
2-3 tablespoons sugar-more if you like
1 1/2  teaspoons vanilla extract (I love Everland vanilla-I buy it at HomeGoods but you can also buy online)

1. Preheat the oven to 375 degrees. 
2. In a large bowl, combine the brown sugar, oats, flour, cinnamon, and salt. Stir to combine. Cut the butter into 8 pieces. Using your fingertips rub the butter and the dry ingredients together until all the ingredients are no longer dry.
3. To prepare the apples, quarter, core, and slice the apples into 1-inch-thick slices. I like to use a 12-blade apple slicer to do all the work. I do not peel the apples. Leaving the peels on saves      time and the skin of the apples will soften when cooked. You can peel your apples if you prefer.
4. Combine the apples, sugar, and apple cider vinegar in a large bowl and toss. Place the apples into a 9 X 13-pan or 9 x 9-inch pan. I prefer to use an au gratin or rectangular dish that provides more surface area. This gives more topping-to-fruit ratio. 
5. Cover the apples with the crisp topping.
6. Bake for 40-50 minutes or until the apples are cooked and soft and bubbling. Let cool for 10 minutes before serving.
7. Combine the sour cream topping ingredients in a bowl. Taste for sweetness as you like.