In a medium bowl, beat butter, confectioners’ sugar, and salt with a hand mixer at medium-high speed until smooth and creamy. Add strawberries, pecans, lemon zest, and vanilla, and beat at medium speed until well combined, increasing speed as needed. Serve immediately, or cover and refrigerate butter for up to 1 week. Let cold butter stand at room temperature until softened, about 30 minutes, before serving.