How to Make It
In a medium saucepan, combine the vanilla seeds and pod with the sugar, 2 1/2 cups of water and 3 pieces of the lemon zest. Bring to a simmer, stirring to dissolve the sugar. Remove the pan from the heat and let steep for 30 minutes. Strain the syrup through a fine sieve. Return the syrup to the saucepan and let cool completely.
Add the pears and the remaining 2 pieces of lemon zest to the syrup and bring to a bare simmer. Cook over moderately low heat, turning occasionally, until the pears are just tender, about 20 minutes. Remove the saucepan from the heat and let cool to room temperature. Cover and refrigerate until chilled, about 2 hours.
Place the white chocolate in a heatproof medium bowl. In a small saucepan, combine 1/2 cup of the heavy cream with the corn syrup and vanilla bean paste and bring to a boil. Pour the hot cream over the chocolate and let stand for 1 minute, then whisk until smooth; transfer to a blender. With the machine on, slowly drizzle in the remaining 3/4 cup of heavy cream until smooth. Scrape the vanilla ganache into a large bowl and chill until it is very cold, about 2 hours.
Using a hand mixer, beat the chilled ganache at medium speed until soft peaks form, about 2 minutes. Spread the whipped ganache on the toasts. Slice the pears into thin wedges; arrange on top. Garnish with pomegranate seeds and serve.
Pain de mie is sliced packaged white bread that’s available at bakeries.