In a medium saucepan over medium-high heat, bring butter and cream to a boil. Remove from heat. Add 4 oz semisweet chocolate chips, stirring until melted. Stir in cookie crumbs.

Line a square baking pan with tin foil, overlapping sides. (It doesn't matter what size pan.)Spread truffle mixture evenly into pan. Chill until firm, about 1 hour.

Remove mixture from pan. Cut into 36 uniform pieces. Shape each piece into an oval and place on waxed paper lined baking sheet. Press down slightly to flatten the bottom, but not the top. Chill until firm.

In the top of a double boiler, melt remaining semisweet chocolate chips and shortening until smooth, stirring often. Remove from heat.

Place a shaped truffle on a fork. Holding it over the pan, spoon chocolate over the truffle. Return truffle to baking sheet. Repeat with all truffles. Chill until set.

Melt White chocolate and stir until smooth. Place truffles on a rack over waxed paper. Drizzle white chocolate over eggs. If using, place Easter sprinkles on truffles securing with melted white chocolate. Chill truffles until chocolate is set.

Store in an airtight container.