#Region "- Cookies -"

        ''' <summary>
        ''' Reads the cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <returns></returns>
        Protected Function ReadCookie(ByVal cookieName As String) As String
            Return If(Not Me.Request.Cookies(cookieName) Is Nothing, Me.Server.HtmlEncode(Me.Request.Cookies(cookieName).Value).Trim(), String.Empty)
        End Function

        ''' <summary>
        ''' Writes a cookie and auto sets the expire date to as current day plus one.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <param name="cookieValue">The cookie value.</param>
        Protected Sub WriteCookie(ByVal cookieName As String, ByVal cookieValue As String, ByVal isHttpCookie As Boolean)
            Dim aCookie As New HttpCookie(cookieName) With {.Value = cookieValue, .Expires = DateTime.Now.AddDays(1), .HttpOnly = isHttpCookie}
            Me.Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Writes a cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <param name="cookieValue">The cookie value.</param>
        Protected Sub WriteCookie(ByVal cookieName As String, ByVal cookieValue As String, ByVal isHttpCookie As Boolean, ByVal cookieExpireDate As DateTime)
            Dim aCookie As New HttpCookie(cookieName) With {.Value = cookieValue, .Expires = cookieExpireDate, .HttpOnly = isHttpCookie}
            Me.Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Deletes a single cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        Protected Sub DeleteCookie(ByVal cookieName As String)
            Dim aCookie As New HttpCookie(cookieName) With {.Expires = Date.Now.AddDays(-1)}
            Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Deletes all the cookies available to the application.
        ''' </summary>
        ''' <remarks>The technique creates a new cookie with the same name as the cookie to be deleted, but to set the cookie's expiration to a date earlier than today.</remarks>
        Protected Sub DeleteAllCookies()
            Dim i As Integer
            For i = 0 To Me.Request.Cookies.Count - 1
                Me.Response.Cookies.Add(New HttpCookie(Me.Request.Cookies(i).Name) With {.Expires = DateTime.Now.AddDays(-1)})
            Next
        End Sub

#End Region

#Region "- Cookies -"

        ''' <summary>
        ''' Reads the cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <returns></returns>
        Protected Function ReadCookie(ByVal cookieName As String) As String
            Return If(Not Me.Request.Cookies(cookieName) Is Nothing, Me.Server.HtmlEncode(Me.Request.Cookies(cookieName).Value).Trim(), String.Empty)
        End Function

        ''' <summary>
        ''' Writes a cookie and set expire date to the current date, plus one day.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <param name="cookieValue">The cookie value.</param>
        Protected Sub WriteCookie(ByVal cookieName As String, ByVal cookieValue As String, ByVal isHttpCookie As Boolean)
            Dim aCookie As New HttpCookie(cookieName) With {.Value = cookieValue, .Expires = DateTime.Now.AddDays(1), .HttpOnly = isHttpCookie}
            Me.Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Writes a cookie and set expire date to the current date, plus one day.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <param name="cookieValue">The cookie value.</param>
        Protected Sub WriteCookie(ByVal cookieName As String, ByVal cookieValue As String, ByVal isHttpCookie As Boolean, ByVal cookieExpireDate As DateTime)
            Dim aCookie As New HttpCookie(cookieName) With {.Value = cookieValue, .Expires = cookieExpireDate, .HttpOnly = isHttpCookie}
            Me.Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Deletes a single cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        Protected Sub DeleteCookie(ByVal cookieName As String)
            Dim aCookie As New HttpCookie(cookieName) With {.Expires = Date.Now.AddDays(-1)}
            Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Deletes all the cookies available to the application.
        ''' </summary>
        ''' <remarks>The technique creates a new cookie with the same name as the cookie to be deleted, but to set the cookie's expiration to a date earlier than today.</remarks>
        Protected Sub DeleteAllCookies()
            Dim i As Integer
            For i = 0 To Me.Request.Cookies.Count - 1
                Me.Response.Cookies.Add(New HttpCookie(Me.Request.Cookies(i).Name) With {.Expires = DateTime.Now.AddDays(-1)})
            Next
        End Sub

#End Region

#Region "- Cookies -"

        ''' <summary>
        ''' Reads the cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <returns></returns>
        Protected Function ReadCookie(ByVal cookieName As String) As String
            Return If(Not Me.Request.Cookies(cookieName) Is Nothing, Me.Server.HtmlEncode(Me.Request.Cookies(cookieName).Value).Trim(), String.Empty)
        End Function

        ''' <summary>
        ''' Writes a cookie and set expire date to the current date, plus one day.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <param name="cookieValue">The cookie value.</param>
        Protected Sub WriteCookie(ByVal cookieName As String, ByVal cookieValue As String, ByVal isHttpCookie As Boolean)
            Dim aCookie As New HttpCookie(cookieName) With {.Value = cookieValue, .Expires = DateTime.Now.AddDays(1), .HttpOnly = isHttpCookie}
            Me.Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Writes a cookie and set expire date to the current date, plus one day.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        ''' <param name="cookieValue">The cookie value.</param>
        Protected Sub WriteCookie(ByVal cookieName As String, ByVal cookieValue As String, ByVal isHttpCookie As Boolean, ByVal cookieExpireDate As DateTime)
            Dim aCookie As New HttpCookie(cookieName) With {.Value = cookieValue, .Expires = cookieExpireDate, .HttpOnly = isHttpCookie}
            Me.Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Deletes a single cookie.
        ''' </summary>
        ''' <param name="cookieName">Name of the cookie.</param>
        Protected Sub DeleteCookie(ByVal cookieName As String)
            Dim aCookie As New HttpCookie(cookieName) With {.Expires = Date.Now.AddDays(-1)}
            Response.Cookies.Add(aCookie)
        End Sub

        ''' <summary>
        ''' Deletes all the cookies available to the application.
        ''' </summary>
        ''' <remarks>The technique creates a new cookie with the same name as the cookie to be deleted, but to set the cookie's expiration to a date earlier than today.</remarks>
        Protected Sub DeleteAllCookies()
            Dim i As Integer
            For i = 0 To Me.Request.Cookies.Count - 1
                Me.Response.Cookies.Add(New HttpCookie(Me.Request.Cookies(i).Name) With {.Expires = DateTime.Now.AddDays(-1)})
            Next
        End Sub

#End Region

You should include these Cookie helpers in your base page class.  Enjoy!

Server-side Cookie Helper Methods

aspnet

VB.NET