Preheat the oven to 350 degrees F and lightly grease 11 (3-ounce) silicone cupcake molds. (Or, alternatively, grease and flour 10 regular muffin wells in a muffin tin.)
Sift together the flour, sugar, baking powder and salt and transfer to a standing electric mixer fitted with a paddle attachment. Mix briefly on low speed to combine. Add the butter, little by little, and continue to process on low speed until the mixture resembles coarse crumbs with pea-sized pieces.
In a small bowl, whisk together the eggs, pumpkin, spices and vanilla. While the mixer is still running at low speed, drizzle half of the liquid ingredients into the mixer and continue to mix until just combined. Increase the speed on the mixer to medium-high and mix until light and fluffy, 1 to 2 minutes. Add the remaining liquid ingredients in a slow, steady stream, and continue to mix until thoroughly incorporated, about 15 seconds longer, scraping down the sides of the mixer bowl as necessary. Don't worry if the mixture appears slightly curdled.
Divide the mixture between 10 regular sized buttered muffin wells or 11 (3-ounce) silicone muffin cups - the wells should be filled about 2/3 of the way. Bake for 16 to 18 minutes, or until golden brown on top and a toothpick inserted in the center comes out clean. Transfer to cooling racks and let cool for 5 minutes. Make sure not to peel silicone olds off of cupcakes. Invert muffin tins or holders and muffins should release easily. Frost with the Butterscotch Frosting, tinted with colors if desired.*
*Note: We tested these muffins in silicone, pumpkin-shaped cups and colored the frosting orange and black and decorated the tops of the muffins accordingly for Halloween.
6 ounces cream cheese, softened at room temperature
1 cup confectioners' sugar
2 tablespoons unsalted butter
1/4 teaspoon salt
6 tablespoons Butterscotch Sauce, recipe follows, or store-bought butterscotch sauce
In the bowl of a standing electric mixer, combine the cream cheese, confectioners' sugar, butter, and salt, and beat until smooth and creamy, 3 to 4 minutes. Reduce the speed to low and add the Butterscotch Sauce, 1 tablespoon at a time, and mix until thoroughly incorporated, stopping to scrape down the sides of the bowl as necessary. Chill slightly if frosting cupcakes.
Yield: enough frosting for 1 dozen cupcakes.
Combine the sugar, water, and lemon juice in a medium, heavy saucepan and cook over medium-high heat, stirring, until the sugar dissolves. Let boil without stirring until the mixture becomes a deep amber color, 3 to 4 minutes, watching closely so it doesn't burn. Remove the pan from the heat. Add the butter and swirl the pan to melt it, about 1 minute. Return to the heat and bring to a boil. Add the cream, whisk to combine, and remove from the heat. Add 2 tablespoons of the milk, and up to 2 tablespoons more, until desired consistency is achieved.
Cool until just warm before serving. (The sauce will thicken as it cools.)