Put the shortening in a small saucepan over low heat. Heat just until it melts.

Remove from the heat and allow to cool.

Preheat the oven to 375°F.

Line two baking sheets with nonstick silicone baking mats or parchment paper. (Alternatively, use nonstick baking sheets or lightly butter conventional baking sheets.) Set aside.

Combine the flour and baking powder in a mixing bowl. Set aside.

Combine the eggs and granulated sugar in the bowl of a standing electric mixer fitted with the paddle. Beat on low speed to just combine; then increase the speed to medium and beat for about 10 minutes, or until very light and fluffy.

Add the orange juice and zest along with the vanilla and beat to blend, then beat in the cooled, melted shortening.

Gradually add the flour mixture, beating to incorporate. When the dough is well blended, remove the bowl from the mixer and scrape the paddle clean.

Place the confectioners' sugar in a large, shallow container.

Using about a teaspoon of dough, form balls and roll each in the confectioners' sugar.

Place the cookies, about 1 inch apart, on the prepared baking sheets.

Place in the oven and bake for about 10 minutes, or until golden brown.

Remove from the oven and, using a metal spatula, transfer the cookies to wire racks to cool.

Store in layers separated by waxed paper, airtight, at room temperature for up to a week.

Makes about 4 dozen cookies.